@article {2546,
	title = {Ca2+ binding by domain 2 plays a critical role in the activation and stabilization of gelsolin},
	journal = {Proceedings of the National Academy of Sciences of the United States of America},
	volume = {106},
	number = {33},
	year = {2009},
	note = {ISI Document Delivery No.: 484WETimes Cited: 5Cited Reference Count: 30Nag, Shalini Ma, Qing Wang, Hui Chumnarnsilpa, Sakesit Lee, Wei Lin Larsson, Marten Kannan, Balakrishnan Hernandez-Valladarez, Maria Burtnick, Leslie D. Robinson, Robert C.},
	month = {Aug},
	pages = {13713-13718},
	type = {Article},
	abstract = {Gelsolin consists of six homologous domains (G1-G6), each containing a conserved Ca-binding site. Occupation of a subset of these sites enables gelsolin to sever and cap actin filaments in a Ca-dependent manner. Here, we present the structures of Ca-free human gelsolin and of Ca-bound human G1-G3 in a complex with actin. These structures closely resemble those determined previously for equine gelsolin. However, the G2 Ca-binding site is occupied in the human G1-G3/actin structure, whereas it is vacant in the equine version. In-depth comparison of the Ca-free and Ca-activated, actin-bound human gelsolin structures suggests G2 and G6 to be cooperative in binding Ca2+ and responsible for opening the G2-G6 latch to expose the F-actin-binding site on G2. Mutational analysis of the G2 and G6 Ca-binding sites demonstrates their interdependence in maintaining the compact structure in the absence of calcium. Examination of Ca binding by G2 in human G1-G3/actin reveals that the Ca2+ locks the G2-G3 interface. Thermal denaturation studies of G2-G3 indicate that Ca binding stabilizes this fragment, driving it into the active conformation. The G2 Ca-binding site is mutated in gelsolin from familial amyloidosis (Finnish-type) patients. This disease initially proceeds through protease cleavage of G2, ultimately to produce a fragment that forms amyloid fibrils. The data presented here support a mechanism whereby the loss of Ca binding by G2 prolongs the lifetime of partially activated, intermediate conformations in which the protease cleavage site is exposed.},
	keywords = {actin, AMYLOIDOGENESIS, biosynthesis, calcium, calcium activated, calcium dependent, FAMILIAL AMYLOIDOSIS, IDENTIFICATION, PLASMA GELSOLIN, PROTEIN, SITE, TERMINAL HALF, TIRF},
	isbn = {0027-8424},
	url = {<Go to ISI>://000269078700018},
	author = {Nag, S. and Ma, Q. and Wang, H. and Chumnarnsilpa, S. and Lee, W. L. and Larsson, M. and Kannan, B. and Hernandez-Valladarez, M. and Burtnick, L. D. and Robinson, R. C.}
}
@article {2510,
	title = {The Engineering of Bacteria Bearing Azido-Pseudaminic Acid-Modified Flagella},
	journal = {Chembiochem},
	volume = {10},
	number = {8},
	year = {2009},
	note = {ISI Document Delivery No.: 452SMTimes Cited: 3Cited Reference Count: 24Liu, Feng Aubry, Annie J. Schoenhofen, Ian C. Logan, Susan M. Tanner, Martin E.},
	month = {May},
	pages = {1317-1320},
	type = {Article},
	keywords = {4, 6-DEHYDRATASE, azides, biosynthesis, C. jejuni, CAMPYLOBACTER-JEJUNI, cell surfaces, flagella, FUNCTIONAL-CHARACTERIZATION, HELICOBACTER-PYLORI, IDENTIFICATION, METABOLISM, PATHWAY, PROTEINS, PseB, reaction, Staudinger, UDP-N-ACETYLGLUCOSAMINE},
	isbn = {1439-4227},
	url = {<Go to ISI>://000266561500009},
	author = {Liu, F. and Aubry, A. J. and Schoenhofen, I. C. and Logan, S. M. and Tanner, M. E.}
}
@article {2343,
	title = {Fruit-Surface Flavonoid Accumulation in Tomato Is Controlled by a SIMYB12-Regulated Transcriptional Network},
	journal = {Plos Genetics},
	volume = {5},
	number = {12},
	year = {2009},
	note = {ISI Document Delivery No.: 542CTTimes Cited: 3Cited Reference Count: 58Adato, Avital Mandel, Tali Mintz-Oron, Shira Venger, Ilya Levy, Dorit Yativ, Merav Dominguez, Eva Wang, Zhonghua De Vos, Ric C. H. Jetter, Reinhard Schreiber, Lukas Heredia, Antonio Rogachev, Ilana Aharoni, Asaph},
	month = {Dec},
	pages = {23},
	type = {Article},
	abstract = {The cuticle covering plants{\textquoteright} aerial surfaces is a unique structure that plays a key role in organ development and protection against diverse stress conditions. A detailed analysis of the tomato colorless-peel y mutant was carried out in the framework of studying the outer surface of reproductive organs. The y mutant peel lacks the yellow flavonoid pigment naringenin chalcone, which has been suggested to influence the characteristics and function of the cuticular layer. Large-scale metabolic and transcript profiling revealed broad effects on both primary and secondary metabolism, related mostly to the biosynthesis of phenylpropanoids, particularly flavonoids. These were not restricted to the fruit or to a specific stage of its development and indicated that the y mutant phenotype is due to a mutation in a regulatory gene. Indeed, expression analyses specified three R2R3-MYB-type transcription factors that were significantly down-regulated in the y mutant fruit peel. One of these, SIMYB12, was mapped to the genomic region on tomato chromosome 1 previously shown to harbor the y mutation. Identification of an additional mutant allele that co-segregates with the colorless-peel trait, specific down-regulation of SlMYB12 and rescue of the y phenotype by overexpression of SlMYB12 on the mutant background, confirmed that a lesion in this regulator underlies the y phenotype. Hence, this work provides novel insight to the study of fleshy fruit cuticular structure and paves the way for the elucidation of the regulatory network that controls flavonoid accumulation in tomato fruit cuticle.},
	keywords = {AFFECTS VEGETATIVE DEVELOPMENT, ARABIDOPSIS-THALIANA, EVOLUTION, EXPRESSION, GENE, IDENTIFICATION, LIQUID-CHROMATOGRAPHY, METABOLISM, PHENYLPROPANOID BIOSYNTHESIS, REGULATOR},
	isbn = {1553-7390},
	url = {<Go to ISI>://000273469700027},
	author = {Adato, A. and Mandel, T. and Mintz-Oron, S. and Venger, I. and Levy, D. and Yativ, M. and Dominguez, E. and Wang, Z. H. and De Vos, R. C. H. and Jetter, R. and Schreiber, L. and Heredia, A. and Rogachev, I. and Aharoni, A.}
}
@article {2456,
	title = {Nanomechanical Properties of Tenascin-X Revealed by Single-Molecule Force Spectroscopy},
	journal = {Journal of Molecular Biology},
	volume = {385},
	number = {4},
	year = {2009},
	note = {ISI Document Delivery No.: 403HJTimes Cited: 4Cited Reference Count: 35Jollymore, Ashlee Lethias, Claire Peng, Qing Cao, Yi Li, Hongbin},
	month = {Jan},
	pages = {1277-1286},
	type = {Article},
	abstract = {Tenascin-X is an extracellular matrix protein and binds a variety of molecules in extracellular matrix and on cell membrane. Tenascin-X plays important roles in regulating the structure and mechanical properties of connective tissues. Using single-molecule atomic force microscopy, we have investigated the mechanical properties of bovine tenascin-X in detail. Our results indicated that tenascin-X is an elastic protein and the fibronectin type III (FnIII) domains can unfold under a stretching force and refold to regain their mechanical stability upon the removal of the stretching force. All the 30 FnIII domains of tenascin-X show similar mechanical stability, mechanical unfolding kinetics, and contour length increment upon domain unfolding, despite their large sequence diversity. In contrast to the homogeneity in their mechanical unfolding behaviors, FnIII domains fold at different rates. Using the 10th FnIII domain of tenascin-X (TNXfn10) as a model system, we constructed a polyprotein chimera composed of alternating TNXfn10 and GB1 domains and used. atomic force microscopy to confirm that the mechanical properties of TNXfn10 are consistent with those of the FnIII domains of tenascin-X These results lay the foundation to further study the mechanical properties of individual FnIII domains and establish the relationship between point mutations and mechanical phenotypic effect on tenascin-X Moreover, our results provided the opportunity to compare the mechanical properties and design of different forms of tenascins. The comparison between tenascin-X and tenascin-C revealed interesting common as well as distinguishing features for mechanical unfolding and folding of tenascin-C and tenascin-X and will open up new avenues to investigate the mechanical. functions and architectural design of different forms of tenascins. (C) 2008 Elsevier Ltd. All rights reserved.},
	keywords = {AFM, BINDING, DEFICIENCY, DOMAINS, FAMILY, FnIII domains, IDENTIFICATION, III MODULES, MECHANICAL STABILITY, mechanical unfolding, microscopy, PROTEIN, single molecule force spectroscopy, tenascin},
	isbn = {0022-2836},
	url = {<Go to ISI>://000263073400022},
	author = {Jollymore, A. and Lethias, C. and Peng, Q. and Cao, Y. and Li, H. B.}
}
@article {2103,
	title = {Current approaches for global post-translational modification discovery and mass spectrometric analysis},
	journal = {Analytica Chimica Acta},
	volume = {627},
	number = {1},
	year = {2008},
	note = {ISI Document Delivery No.: 358IYTimes Cited: 13Cited Reference Count: 77Hoffman, Michael D. Sniatynski, Matthew J. Kast, JuergenSp. Iss. SI},
	month = {Oct},
	pages = {50-61},
	type = {Review},
	abstract = {More and more attention is being focused on the analysis of post-translational modifications (PTMs) on proteins as researchers are continually learning how essential they are for proper cellular function. As there are hundreds of different types of known PTMs, traditional methods of modification analysis are incapable of comprehensively monitoring for post-translational modifications, a task which is a necessity for truly understanding a cell{\textquoteright}s biology. This review highlights recent developments in novel multiplexed methods of PTM analysis including: fluorescent stain and immuno-based methods, hardware-based mass spectrometric methods and computational-based mass spectrometric methods. Many of these techniques show great promise and will likely be a valuable resource for the biological community. (C) 2008 Elsevier B.V. All rights reserved.},
	keywords = {computational, glycosylation, IDENTIFICATION, IONIZATION, marker ion, MASS SPECTROMETRY, MODIFIED PEPTIDES, neutral loss, post-translational modifications, protein array, PROTEIN-PHOSPHORYLATION, PROTEOMIC ANALYSIS, S-NITROSYLATION, SEQUENCES, SIGNALING NETWORKS, SPECTRA},
	isbn = {0003-2670},
	url = {<Go to ISI>://000259911600005},
	author = {Hoffman, M. D. and Sniatynski, M. J. and Kast, J.}
}
@article {2121,
	title = {Making connections for life: an in vivo map of the yeast interactome},
	journal = {Hfsp Journal},
	volume = {2},
	number = {5},
	year = {2008},
	note = {ISI Document Delivery No.: 355VHTimes Cited: 1Cited Reference Count: 28Kast, Juergen},
	month = {Oct},
	pages = {244-250},
	type = {Article},
	abstract = {Proteins are the true workhorses of any cell. To carry out specific tasks, they frequently bind other molecules in their surroundings. Due to their structural complexity and flexibility, the most diverse array of interactions is seen with other proteins. The different geometries and affinities available for such interactions typically bestow specific functions on proteins. Having available a map of protein - protein interactions is therefore of enormous importance for any researcher interested in gaining insight into biological systems at the level of cells and organisms. In a recent report, a novel approach has been employed that relies on the spontaneous folding of complementary enzyme fragments fused to two different proteins to test whether these interact in their actual cellular context [Tarassov et al., Science 320, 1465-1470 (2008)]. Genome- wide application of this protein- fragment complementation assay has resulted in the first map of the in vivo interactome of Saccharomyces cerevisiae. The current data show striking similarities but also significant differences to those obtained using other large- scale approaches for the same task. This warrants a general discussion of the current state of affairs of protein - protein interaction studies and foreseeable future trends, highlighting their significance for a variety of applications and their potential to revolutionize our understanding of the architecture and dynamics of biological systems.},
	keywords = {AMINO-ACIDS, CELL-CULTURE, COMPLEXES, CROSS-LINKING, IDENTIFICATION, MASS-SPECTROMETRY, PROTEIN-PROTEIN INTERACTIONS, QUANTIFICATION, QUANTITATION, SACCHAROMYCES-CEREVISIAE},
	isbn = {1955-2068},
	url = {<Go to ISI>://000259736700002},
	author = {Kast, J.}
}
@article {2193,
	title = {Mechanistic studies on PseB of pseudaminic acid biosynthesis: A UDP-N-acetylglucosamine 5-inverting 4,6-dehydratase},
	journal = {Bioorganic Chemistry},
	volume = {36},
	number = {4-6},
	year = {2008},
	note = {ISI Document Delivery No.: 386TPTimes Cited: 2Cited Reference Count: 33Morrison, James P. Schoenhofen, Ian C. Tanner, Martin E.},
	month = {Aug-Dec},
	pages = {312-320},
	type = {Article},
	abstract = {UDP-N-acetylglucosamine 5-inverting 4,6-dehydratase (PseB) is a unique sugar nucleotide dehydratase that inverts the C-5 {\textquoteright}{\textquoteright} stereocentre during conversion of UDP-N-acetylglucosamine to UDP-2-acetamido2,6-dideoxy-beta-L-arabino-hexos-4-ulose. PseB catalyzes the first step in the biosynthesis of pseudaminic acid, which is found as a post-translational modification on the flagellin of Campylobacter jejuni and Helicobacter pylori. PseB is proposed to use its tightly bound NADP(+) to oxidize UDP-GlcNAc at C-4 {\textquoteright}{\textquoteright}, enabling dehydration. The alpha,beta unsaturated ketone intermediate is then reduced by delivery of the hydride to C-6 {\textquoteright}{\textquoteright} and a proton to C-5 {\textquoteright}{\textquoteright}. Consistent with this, PseB from C. jejuni has been found to incorporate deuterium into the C-5 {\textquoteright}{\textquoteright} position of product during catalysis in D2O. Likewise, PseB catalyzes solvent isotope exchange into the H-5 {\textquoteright}{\textquoteright} position of product, and eliminates HF from the alternate Substrate, UDP-6-deoxy-6-fluoro-GlcNAc. Mutants of the putative catalytic residues aspartate 126, lysine 127 and tyrosine 135 have severely compromised dehydratase, solvent isotope exchange, and HF elimination activities. (C) 2008 Elsevier Inc. All rights reserved.},
	keywords = {6-DEHYDRATASE, Campylobacter jejuni, CAMPYLOBACTER-JEJUNI, dehydratase, DTDP-GLUCOSE 4, ENZYMES, FLAA1, FUNCTIONAL-CHARACTERIZATION, GDP-MANNOSE 4, HELICOBACTER-PYLORI, IDENTIFICATION, Inverting, MOTILITY, PATHWAY, PseB, Pseudaminic acid, UDP-N-acetylglucosamine 5-inverting 4},
	isbn = {0045-2068},
	url = {<Go to ISI>://000261905800019},
	author = {Morrison, J. P. and Schoenhofen, I. C. and Tanner, M. E.}
}
@article {2277,
	title = {Phosphorylation of U24 from Human Herpes Virus type 6 (HHV-6) and its potential role in mimicking myelin basic protein (MBP) in multiple sclerosis},
	journal = {Febs Letters},
	volume = {582},
	number = {18},
	year = {2008},
	note = {ISI Document Delivery No.: 332UKTimes Cited: 2Cited Reference Count: 31Tait, Andrew R. Straus, Suzana K.},
	month = {Aug},
	pages = {2685-2688},
	type = {Article},
	abstract = {Myelin basic protein (MBP) from multiple sclerosis ( MS) patients contains lower levels of phosphorylation at Thr97 than normal individuals. The significance of phosphorylation at this site is not fully understood, but it is proposed to play a role in the normal functioning of MBP. Human Herpesvirus Type 6 encodes the protein U24, which has tentatively been implicated in the pathology of MS. U24 shares a 7 amino acid stretch encompassing the Thr97 phosphorylation site of MBP: PRTPPPS. We demonstrate using a combination of mass spectrometry, thin layer chromatography and autoradiography, that U24 can be phosphorylated at the equivalent threonine. Phospho-U24 may confound signalling or other pathways in which phosphorylated MBP may participate, precipitating a pathological process.},
	keywords = {BINDING, EXPRESSION, HUMAN-HERPESVIRUS-6, IDENTIFICATION, KINASE, MEMBRANE MICRODOMAINS, mimicry, myelin, PHOSPHORYLATION, POSTTRANSLATIONAL MODIFICATIONS, SITE, T-ANTIGEN, U24},
	isbn = {0014-5793},
	url = {<Go to ISI>://000258108400002},
	author = {Tait, A. R. and Straus, S. K.}
}
@article {2306,
	title = {A switching rule for plastics identification in electronics recycling},
	journal = {International Journal of Computer Integrated Manufacturing},
	volume = {21},
	number = {6},
	year = {2008},
	note = {ISI Document Delivery No.: 339PRTimes Cited: 0Cited Reference Count: 39Williams, J. A. S. Qu, X. Rios, P. Wieland, J. Grant, E.},
	pages = {730-743},
	type = {Article},
	abstract = {The looming obsolescence of 3 billion consumer electronics by 2010 calls for effective recycling of 10 billion pounds of high-value engineering thermoplastics. Because general shredding operations generate mixed plastics of low value, a switching rule is needed rapidly to identify plastics for sortation by colour and type to increase plastics-to-plastics recycling value. The current paper develops a heuristic rule to determine the thresholds for a switching rule that reduces set-up time while managing queue space. Our recycling system is modelled as a multiclass queuing network in a simulation model. Results indicate that laser identification probe utilization, setups, and queue space are sensitive to the switching rule. Our work contributes important insights into the relationship between traffic intensity, setup time, and queue capacity, and generalizes to multiclass queuing systems in other applications.},
	keywords = {electronics recycling, IDENTIFICATION, multiclass queuing network, NETWORKS, OF-LIFE ELECTRONICS, plastics, RECOVERY, scheduling, switching rules},
	isbn = {0951-192X},
	url = {<Go to ISI>://000258590000009},
	author = {Williams, J. A. S. and Qu, X. and Rios, P. and Wieland, J. and Grant, E.}
}
@article {2276,
	title = {Utility of formaldehyde cross-linking and mass spectrometry in the study of protein-protein interactions},
	journal = {Journal of Mass Spectrometry},
	volume = {43},
	number = {6},
	year = {2008},
	note = {ISI Document Delivery No.: 319PPTimes Cited: 22Cited Reference Count: 54Sutherland, Brent W. Toews, Judy Kast, Juergen},
	month = {Jun},
	pages = {699-715},
	type = {Article},
	abstract = {For decades, formaldehyde has been routinely used to cross-link proteins in cells, tissue, and in some instances, even entire organisms. Due to its small size, formaldehyde can readily permeate cell walls and membranes, resulting in efficient cross-linking, i.e. the formation of covalent bonds between proteins, DNA, and other reactive molecules. Indeed, formaldehyde cross-linking is an instrumental component of many mainstream analytical/cell biology techniques including chromatin immunoprecipitation (ChIP) of protein-DNA complexes found in nuclei; immunohistological analysis of protein expression and localization within cells, tissues, and organs; and mass spectrometry (MS)-compatible silver-staining methodologies used to visualize low abundance proteins in polyacrylamide gels. However, despite its exquisite suitability for use in the analysis of protein environments within cells, formaldehyde has yet to be commonly employed in the directed analysis of protein-protein interactions and cellular networks. The general purpose of this article is to discuss recent advancements in the use of formaldehyde cross-linking in combination with MS-based methodologies. Key advantages and limitations to the use of formaldehyde over other cross-linkers and technologies currently used to study protein-protein interactions are highlighted, and formaldehyde-based experimental approaches that are proving very promising in their ability to accurately and efficiently identify novel protein-protein and multiprotein interaction complexes are presented. Copyright (c) 2008 John Wiley \& Sons, Ltd.},
	keywords = {ANTIGEN-RETRIEVAL, CHROMATIN IMMUNOPRECIPITATION, COMPLEXES, CROSS-LINKING, FORMALDEHYDE, IDENTIFICATION, IMMUNOHISTOCHEMISTRY, INTERACTION NETWORKS, MASS SPECTROMETRY, PARAFFIN-EMBEDDED TISSUE, protein interactions, PROTEOMICS, review, SURFACE-TOPOLOGY, THROUGHPUT},
	isbn = {1076-5174},
	url = {<Go to ISI>://000257176400001},
	author = {Sutherland, B. W. and Toews, J. and Kast, J.}
}
@article {1368,
	title = {Calcium ion exchange in crystalline gelsolin},
	journal = {Journal of Molecular Biology},
	volume = {357},
	number = {3},
	year = {2006},
	note = {ISI Document Delivery No.: 030IYTimes Cited: 6Cited Reference Count: 24},
	month = {Mar},
	pages = {773-782},
	type = {Article},
	abstract = {Gelsolin is a calcium and pH-sensitive modulator of actin filament length. Here, we use X-ray crystallography to examine the extraction and exchange of calcium ions from their binding sites in different crystalline forms of the activated N and C-terminal halves of gelsolin, G1-G3 and G4-G6, respectively. We demonstrate that the combination of calcium and low pH activating conditions do not induce conformational changes in G4-G6 beyond those elicited by calcium alone. EGTA is able to remove calcium ions bound to the type I and type II metal ion-binding sites in G4-G6. Constrained by crystal contacts and stabilized by interdomain interaction surfaces, the gross structure of calcium-depleted G4-G6 remains that of the activated form. However, high-resolution details of changes in the ion-binding sites may represent the initial steps toward restoration of the arrangement of domains found in the calcium-free inactive form of gelsolin in solution. Furthermore, bathing crystals with the trivalent calcium ion mimic, Tb3+, results in anomalous scattering data that permit unequivocal localization of terbium ions in each of the proposed type I and type II ion-binding sites of both halves of gelsolin. In contrast to predictions based on solution studies, we find that no calcium ion is immune to exchange. (c) 2006 Elsevier Ltd. All rights reserved.},
	keywords = {actin, ACTIN MONOMER, ACTIVATION, apoptosis, BINDING-SITE, C-TERMINAL HALF, calcium activation, COMPLEX, CONFORMATIONAL CHANGE, DOMAINS, ELECTRON-DENSITY MAPS, gelsolin, IDENTIFICATION, MECHANISMS, protein crystallography},
	isbn = {0022-2836},
	url = {<Go to ISI>://000236629300008},
	author = {Chumnarnsilpa, S. and Loonchanta, A. and Xue, B. and Choe, H. and Urosev, D. and Wang, H. and Lindberg, U. and Burtnick, L. D. and Robinson, R. C.}
}
@article {1437,
	title = {Expanding the thioglycoligase strategy to the synthesis of alpha-linked thioglycosides allows structural investigation of the parent enzyme/substrate complex},
	journal = {Journal of the American Chemical Society},
	volume = {128},
	number = {7},
	year = {2006},
	note = {ISI Document Delivery No.: 015PITimes Cited: 21Cited Reference Count: 12},
	month = {Feb},
	pages = {2202-2203},
	type = {Article},
	keywords = {ARCHAEON, DISEASE TYPE-II, IDENTIFICATION, MOLECULAR CHARACTERIZATION, MUTATIONS, PHENOTYPE},
	isbn = {0002-7863},
	url = {<Go to ISI>://000235562900024},
	author = {Kim, Y. W. and Lovering, A. L. and Chen, H. M. and Kantner, T. and McIntosh, L. P. and Strynadka, N. C. J. and Withers, S. G.}
}
@article {1464,
	title = {PseG of pseudaminic acid biosynthesis - A UDP-sugar hydrolase as a masked glycosyltransferase},
	journal = {Journal of Biological Chemistry},
	volume = {281},
	number = {30},
	year = {2006},
	note = {ISI Document Delivery No.: 065VFTimes Cited: 12Cited Reference Count: 40Liu, Feng Tanner, Martin E.},
	month = {Jul},
	pages = {20902-20909},
	type = {Article},
	abstract = {The flagellin proteins in pathogenic bacteria such as Campylobacter jejuni and Helicobacter pylori are heavily glycosylated with the nine-carbon alpha-keto acid, pseudaminic acid. The presence of this posttranslational modification is absolutely required for assembly of functional flagella. Since motility is required for colonization, pseudaminic acid biosynthesis represents a virulence factor in these bacteria. Pseudaminic acid is generated from UDP-N-acetylglucosamine in five biosynthetic steps. The final step has been shown to involve the condensation of 2,4-diacetamido- 2,4,6-trideoxy-L-altrose ( 6-deoxy-AltdiNAc) with phosphoenolpyruvate as catalyzed by the enzyme pseudaminic acid synthase, NeuB3. The 6-deoxy-AltdiNAc used in this process is generated from its nucleotide-linked form, UDP-6-deoxy-AltdiNAc, by the action of a hydrolase that cleaves the glycosidic bond and releases UDP. This manuscript describes the first characterization of a UDP-6-deoxy-AltdiNAc hydrolase, namely PseG ( Cj1312) from C. jejuni. The activity of this enzyme is independent of the presence of divalent metal ions, and the values of the catalytic constants were found to be k(cat) = 27 s(-1) and K-m = 174 mu M. The enzyme was shown to hydrolyze the substrate with an overall inversion of stereochemistry at C-1 and to utilize a C-O bond cleavage mechanism during catalysis. These results, coupled with homology comparisons, suggest that the closest ancestors to the hydrolase are members of the metal-independent GT-B family of glycosyltransferases that include the enzyme MurG.},
	keywords = {CAMPYLOBACTER-JEJUNI, FLAGELLIN, FUNCTIONAL-CHARACTERIZATION, GLYCOPROTEINS, glycosylation, HELICOBACTER-PYLORI, IDENTIFICATION, MECHANISM, N-ACETYLGLUCOSAMINE 2-EPIMERASE, NUDIX HYDROLASES, SYNTHASE},
	isbn = {0021-9258},
	url = {<Go to ISI>://000239187300027},
	author = {Liu, F. and Tanner, M. E.}
}
@article {1612,
	title = {The structure of gelsolin bound to ATP},
	journal = {Journal of Molecular Biology},
	volume = {357},
	number = {3},
	year = {2006},
	note = {ISI Document Delivery No.: 030IYTimes Cited: 7Cited Reference Count: 28},
	month = {Mar},
	pages = {765-772},
	type = {Article},
	abstract = {Calcium activation of the actin-modifying properties of gelsolin is sensitive to ATP. Here, we show that soaking calcium-free gelsolin crystals in ATP-containing media results in ATP occupying a site that spans the two pseudosymmetrical halves of the protein. ATP binding involves numerous polar and hydrophobic contacts and is identical for the two copies of gelsolin related by non-crystallographic symmetry within the crystal. The gamma-phosphate of ATP participates in several charge-charge interactions consistent with the preference of gelsolin for ATP, as a binding partner, over ADP. In addition, disruption of the ATP-binding site through Ca2+ activation of gelsolin reveals why ATP binds more tightly to the inactive molecule, and suggests how the binding of ATP may modulate the sensitivity of gelsolin to calcium ions. Similarities between the ATP and PIP2 interactions with the C-terminal half of gelsolin are evident from their overlapping binding sites and in that both molecules bind more tightly in the absence of calcium ions. We propose a model for how PIP2 may bind to calcium-free gelsolin based on the ATP-binding site. (c) 2006 Elsevier Ltd. All rights reserved.},
	keywords = {5-BISPHOSPHATE, actin, ATP, BINDING-SITE, calcium, CRYSTAL-STRUCTURE, DOMAIN, gelsolin, HUMAN-PLASMA GELSOLIN, IDENTIFICATION, PHOSPHATIDYLINOSITOL 4, PIP2, PROTEIN, TERMINAL HALF},
	isbn = {0022-2836},
	url = {<Go to ISI>://000236629300007},
	author = {Urosev, D. and Ma, Q. and Tan, A. L. C. and Robinson, R. C. and Burtnick, L. D.}
}
@article {1526,
	title = {Viable plastics recycling from end-of-life electronics},
	journal = {Ieee Transactions on Electronics Packaging Manufacturing},
	volume = {29},
	number = {1},
	year = {2006},
	note = {ISI Document Delivery No.: 010ALTimes Cited: 3Cited Reference Count: 62},
	month = {Jan},
	pages = {25-31},
	type = {Article},
	abstract = {Millions of end-of-life (EOL) electronic products represent more than one million tons of engineering thermoplastics. The economically and environmentally sound recovery of engineering thermoplastics from EOL electronics is a challenge to the sustainability of electronics manufacturing. In this paper, we review the technologies to separate and identify pure post-consumer plastics from EOL electronics, which are followed by the comparison of electronic plastics recycling processes and the network models for plastics recycling processes. We also review successful plastics recycling practices for electronics. In addition, further research directions for recycling plastics from EOL electronics are discussed.},
	keywords = {DECISION-MAKING, DESIGN, disassembly, end-of-life (EOL) electronics, HIGH-IMPACT POLYSTYRENE, IDENTIFICATION, METHODOLOGY, MODEL, OPTIMIZATION, plastics, PRODUCT, RECOVERY, recycling, SELECTIVE FLOTATION SEPARATION, SEPARATION},
	isbn = {1521-334X},
	url = {<Go to ISI>://000235155100004},
	author = {Qu, X. L. and Williams, J. A. S. and Grant, E. R.}
}
@article {918,
	title = {Arsenic speciation in human urine: are we all the same?},
	journal = {Toxicology and Applied Pharmacology},
	volume = {198},
	number = {3},
	year = {2004},
	note = {ISI Document Delivery No.: 844GRTimes Cited: 26Cited Reference Count: 34},
	month = {Aug},
	pages = {297-306},
	type = {Review},
	abstract = {we studied the arsenic speciation in human urine samples by using high-performance liquid chromatography-inductively coupled plasma-mass spectrometry (HPLC-ICP-MS). We investigated the arsenic speciation in the urine collected from nine volunteers during a 3-day period after a meal of blue mussels, Mytilus edulis. We also studied the effect of cooking on the arsenic speciation. Arsenobetaine and dimethylarsinic acid (DMAA) were the major arsenic metabolites found in the urine samples. Significant amounts of unknown metabolites were also detected. The excretion patterns of arsenic from individuals were generally similar except for two subjects. One of whom excreted high amounts of arsenobetaine even though no arsenic-rich food was eaten for 3 days before the experiment. The results reveal that we need a better understanding of the metabolism of arsenic compounds by human. (C) 2004 Elsevier Inc. All rights reserved.},
	keywords = {arsenic, arsenobetaine, arsenosugar, ENVIRONMENT, HPLC, ICP-MS, IDENTIFICATION, INGESTION, LIQUID-CHROMATOGRAPHY, MASS-SPECTROMETRY, METABOLITES, METHYLATED ARSENICALS, mussel, PRODUCTS, TRIVALENT, urine},
	isbn = {0041-008X},
	url = {<Go to ISI>://000223146600007},
	author = {Lai, V. W. M. and Sun, Y. M. and Ting, E. and Cullen, W. R. and Reimer, K. J.}
}
@article {847,
	title = {Cyclic enterobacterial common antigen: Potential contaminant of bacterially expressed protein preparations},
	journal = {Journal of Biomolecular Nmr},
	volume = {29},
	number = {2},
	year = {2004},
	note = {ISI Document Delivery No.: 801ZPTimes Cited: 5Cited Reference Count: 10},
	month = {Jun},
	pages = {199-204},
	type = {Article},
	abstract = {We have previously reported the identification of the cyclic enterobacterial common antigen (ECACYC) polysaccharide in E. coli strains commonly used for heterologous protein expression (PJA Erbel et al., J. Bacteriol. 185 ( 2003): 1995). Following this initial report, interactions among several NMR groups established that characteristic N-acetyl signals of ECACYC have been observed in N-15-H-1 HSQC spectra of samples of various bacterially-expressed proteins suggesting that this water-soluble carbohydrate is a common contaminant. We provide NMR spectroscopic tools to recognize ECACYC in protein samples, as well as several methods to remove this contaminant. Early recognition of ECA-based NMR signals will prevent time-consuming analyses of this copurifying carbohydrate.},
	keywords = {enterobacterial common antigen, ESCHERICHIA-COLI, heterologous protein expression, IDENTIFICATION, N-acetylated carbohydrate, NMR-SPECTROSCOPY, protein purification},
	isbn = {0925-2738},
	url = {<Go to ISI>://000220134100007},
	author = {Erbel, P. J. A. and Seidel, R. and Macintosh, S. E. and Gentile, L. N. and Amor, J. C. and Kahn, R. A. and Prestegard, J. H. and McIntosh, L. P. and Gardner, K. H.}
}
@article {896,
	title = {Inhibition of Chk1 by the G(2) DNA damage checkpoint inhibitor isogranulatimide},
	journal = {Molecular Cancer Therapeutics},
	volume = {3},
	number = {10},
	year = {2004},
	note = {ISI Document Delivery No.: 862KBTimes Cited: 40Cited Reference Count: 40},
	month = {Oct},
	pages = {1221-1227},
	type = {Article},
	abstract = {Inhibitors of the G(2) DNA damage checkpoint can selectively sensitize cancer cells with mutated p53 to killing by DNA-damaging agents. Isogranulatimide is a G2 checkpoint inhibitor containing a unique indole/maleimide/ imidazole skeleton identified in a phenotypic cell-based screen; however, the mechanism of action of isogranulatimide is unknown. Using natural and synthetic isogranulatimide analogues, we show that the imide nitrogen and a basic nitrogen at position 14 or 15 in the imidazole ring are important for checkpoint inhibition. Isogranulatimide shows structural resemblance to the aglycon of UCN-01, a potent bisindolemaleimide inhibitor of protein kinase Cbeta (IC50, 0.001 mumol/L) and of the checkpoint kinase Chk1 (IC50, 0.007 mumol/L). In vitro kinase assays show that isogranulatimide inhibits Chk1 (IC50, 0.1 mumol/L) but not protein kinase Cbeta. Of 13 additional protein kinases tested, isogranulatimide significantly inhibits only glycogen synthase kinase-3beta (IC50, 0.5 mumol/L). We determined the crystal structure of the Chk1 catalytic domain complexed with isogranulatimicle. Like UCN-01, isogranulatimide binds in the ATP-binding pocket of Chk1 and hydrogen bonds with the backbone carbonyl oxygen of Glu(85) and the amide nitrogen Of Cys(87). Unlike UCN-01, the basic N15 of isogranulatimide interacts with Glu(17), causing a conformation change in the kinase glycine-rich loop that may contribute importantly to inhibition. The mechanism by which isogranulatimide inhibits Chk1 and its favorable kinase selectivity profile make it a promising candidate for modulating checkpoint responses in tumors for therapeutic benefit.},
	keywords = {7-HYDROXYSTAUROSPORINE UCN-01, ACTIVATION, CANCER, CELL-CYCLE, DEPENDENT PROTEIN-KINASE, IDENTIFICATION, MECHANISMS, PHOSPHORYLATION, SPECIFICITY, SUBSTRATE},
	isbn = {1535-7163},
	url = {<Go to ISI>://000224488400006},
	author = {Jiang, X. X. and Zhao, B. G. and Britton, R. and Lim, L. Y. and Leong, D. and Sanghera, J. S. and Zhou, B. B. S. and Piers, E. and Andersen, R. J. and Roberge, M.}
}
@article {663,
	title = {Arsenic methylation by micro-organisms isolated from sheepskin bedding materials},
	journal = {Human \& Experimental Toxicology},
	volume = {22},
	number = {6},
	year = {2003},
	note = {ISI Document Delivery No.: 696NKTimes Cited: 6Cited Reference Count: 48},
	month = {Jun},
	pages = {325-334},
	type = {Article},
	abstract = {Sudden infant death syndrome (SIDS) has been associated with the volatilization of arsenic, antimony or phosphorus compounds from infants{\textquoteright} bedding material by micro-organisms, the so-called {\textquoteright}toxic gas hypothesis{\textquoteright}. The volatilization of arsenic by aerobic micro-organisms isolated from new sheepskin bedding material, as well as on material used by a healthy infant and by an infant who perished of SIDS, was examined. Three fungi were isolated from a piece of sheepskin bedding material on which an infant perished of SIDS, which methylated arsenic to form trimethylarsenic(V) species, precursors to volatile trimethylarsine. These three fungi were identified as Scopulariopsis koningii, Fomitopsis pinicola and Penicillium gladioli by their 26S-ribosomal RNA polymerase chain reaction products. These fungi were not previously known to methylate arsenic. The volatilization of arsenic by these three fungi was then examined. Only R gladioli volatilized arsenic and only under conditions such that the production of sufficient trimethylarsine to be acutely toxic to an infant is unlikely. S. brevicaulis grew on the sheepskin bedding material and evolved a trace amount of trimethylarsine. Known human pathogens such as Mycobacterium neoaurum and Acinetobacter junii were isolated from used bedding.},
	keywords = {ANTIMONY COMPOUNDS, arsenic, BIOMETHYLATION, COT MATTRESSES, fungi, GAS, hypothesis, IDENTIFICATION, INFANT-DEATH-SYNDROME, METHYLATION, SCOPULARIOPSIS-BREVICAULIS, SPECIATION, sudden infant death syndrome, toxic gas, TRIMETHYLARSINE, VOLATILIZATION},
	isbn = {0960-3271},
	url = {<Go to ISI>://000183892800008},
	author = {Lehr, C. R. and Polishchuk, E. and Delisle, M. C. and Franz, C. and Cullen, W. R.}
}
@article {643,
	title = {From the first to the second domain of gelsolin: a common path on the surface of actin?},
	journal = {Febs Letters},
	volume = {552},
	number = {2-3},
	year = {2003},
	note = {ISI Document Delivery No.: 726DKTimes Cited: 22Cited Reference Count: 29},
	month = {Sep},
	pages = {86-90},
	type = {Article},
	abstract = {We present the 2.6. resolution crystal structure of a complex formed between G-actin and gelsolin fragment Met25-GIn160 (G1+). The structure differs from those of other gelsolin domain 1 (G1) complexes in that an additional six amino acid residues from the crucial linker region into gelsolin domain 2 (G2) are visible and are attached securely to the surface of actin. The linker segment extends away from G1 up the face of actin in a direction that infers G2 will bind along the same long-pitch helical strand as the actin bound to G1. This is consistent with a mechanism whereby G2 attaches gelsolin to the side of a filament and then directs G1 toward a position where it would disrupt actin-actin contacts. Alignment of the sequence of the structurally important residues within the G1-G2 linker with those of WH2 (WASp homology domain 2) domain protein family members (e.g. WASp (Wiscott-Aldridge syndrome protein) and thymosin beta4) suggests that the opposing activities of filament assembly and disassembly may exploit a common patch on the surface of actin. (C) 2003 Published by Elsevier B.V. on behalf of the Federation of European Biochemical Societies.},
	keywords = {actin, BINDING, calcium, COMPLEX, crystal structure, DIFFRACTION DATA, F-ACTIN, FILAMENT, gelsolin, IDENTIFICATION, MODEL, MOTILITY, NUCLEATION, WH2 domain},
	isbn = {0014-5793},
	url = {<Go to ISI>://000185583000003},
	author = {Irobi, E. and Burtnick, L. D. and Urosev, D. and Narayan, K. and Robinson, R. C.}
}
@article {498,
	title = {An atmospheric pressure ion lens that improves nebulizer assisted electrospray ion sources},
	journal = {Journal of the American Society for Mass Spectrometry},
	volume = {13},
	number = {8},
	year = {2002},
	note = {ISI Document Delivery No.: 588METimes Cited: 7Cited Reference Count: 27},
	month = {Aug},
	pages = {906-913},
	type = {Article},
	abstract = {An atmospheric pressure ion lens improves the performance and ease of use of a nebulizer assisted electrospray (ion spray) ion source. The lens is comprised of an oblong-shaped stainless steel ring attached to an external high voltage power supply. The lens is located near the tip of the conductive sprayer, and is maintained at a potential less than that of the sprayer. The ion lens improves the shape of the equipotential lines in the vicinity of the sprayer tip. This lens gives approximately a 2-fold reduction in the signal RSD, a 2-fold increase in the ion signal, an increase in the number of multiply charged ions, and a much broader range of usable sprayer positions. (C) 2002 American Society for Mass Spectrometry.},
	keywords = {CAPILLARY-ZONE-ELECTROPHORESIS, DISSOCIATION, EVAPORATION, IDENTIFICATION, INDUCED, INTERFACE, IONIZATION MASS-SPECTROMETRY, JUNCTION, MECHANISM, PROTEIN-ANALYSIS, SHEATHLESS},
	isbn = {1044-0305},
	url = {<Go to ISI>://000177704600002},
	author = {Schneider, B. B. and Douglas, D. J. and Chen, D. D. Y.}
}
@article {348,
	title = {The calcium activation of gelsolin: Insights from the 3 angstrom structure of the G4-G6/actin complex},
	journal = {Journal of Molecular Biology},
	volume = {324},
	number = {4},
	year = {2002},
	note = {ISI Document Delivery No.: 625PRTimes Cited: 48Cited Reference Count: 32},
	month = {Dec},
	pages = {691-702},
	type = {Article},
	abstract = {Gelsolin participates in the reorganization of the actin cytoskeleton that is required during such phenomena as cell movement, cytokinesis, and apoptosis. It consists of six structurally similar domains, G1-G6, which are arranged at resting intracellular levels of calcium ion so as to obscure the three actin-binding surfaces. Elevation of Ca2+ concentrations releases latches within the constrained structure and produces large shifts in the relative positioning of the domains, permitting gelsolin to bind to and sever actin filaments. How Ca2+ is able to activate gelsolin has been a major question concerning the function of this protein. We present the improved structure of the C-terminal half of gelsolin bound to monomeric actin at 3.0 Angstrom resolution. Two classes of Ca2+-binding site are evident on gelsolin: type 1 sites share coordination of Ca2+ with actin, while type 2 sites are wholly contained within gelsolin. This structure of the complex reveals the locations of two novel metal ion-binding sites in domains G5 and G6, respectively. We identify both as type 2 sites. The absolute conservation of the type 2 calcium-ligating residues across the six,domains of gelsolin suggests that this site exists in each of the domains. In total, gelsolin has the potential to bind eight calcium ions, two type 1 and six type 2. The function of the type 2 sites is to facilitate structural rearrangements within gelsolin as part of the activation and actin-binding and severing processes. We propose the novel type 2 site in G6 to be the critical site that initiates overall activation of gelsolin by releasing the tail latch that locks calcium-free gelsolin in a conformation unable to bind actin. (C) 2002 Elsevier Science Ltd. All rights reserved.},
	keywords = {actin, ACTIVATION, ACTOPHORIN, BINDING DOMAIN, CA2+, calcium, CAPPING PROTEIN, F-ACTIN, FAMILIAL AMYLOIDOSIS, FINNISH TYPE, gelsolin, IDENTIFICATION, MECHANISM, PLASMA GELSOLIN, REGULATION, severing},
	isbn = {0022-2836},
	url = {<Go to ISI>://000179825300011},
	author = {Choe, H. and Burtnick, L. D. and Mejillano, M. and Yin, H. L. and Robinson, R. C. and Choe, S.}
}
@article {480,
	title = {Oligomerization-dependent association of the SAM domains from Schizosaccharomyces pombe Byr2 and Ste4},
	journal = {Journal of Biological Chemistry},
	volume = {277},
	number = {42},
	year = {2002},
	note = {ISI Document Delivery No.: 605EATimes Cited: 21Cited Reference Count: 46},
	month = {Oct},
	pages = {39585-39593},
	type = {Article},
	abstract = {SAM (sterile alpha motif) domains are protein-protein interaction modules found in a large number of regulatory proteins. Byr2 and Ste4 are two SAM domain-containing proteins in the mating pheromone response pathway of the fission yeast, Schizosaccharomyces pombe. Byr2 is a mitogen-activated protein kinase kinase kinase that is regulated by Ste4. Tu et al (Tu, H., Barr, M., Dong, D. L., and Wigler, M. (1997) Mol. Cell. Biol. 17, 5876-5887) showed that the isolated SAM domain of Byr2 binds a fragment of Ste4 that contains both a leucine zipper (Ste4-LZ) domain as well as a SAM domain, suggesting that Byr2-SAM and Ste4-SAM may form a hetero-oligomer. Here, we show that the individual SAM domains of Ste4 and Byr2 are monomeric at low concentrations and bind to each other in a 1:1 stoichiometry with a relatively weak dissociation constant of 56 +/- 3 mum. Inclusion of the Ste4-LZ domain, which determines the oligomeric state of Ste4, has a dramatic effect on binding affinity, however. We find that the Ste4-LZ domain is trimeric and, when included with the Ste4-SAM domain, yields a 3:1 Ste4-LZ-SAM:Byr2-SAM complex with a tight dissociation constant of 19 +/- 4 nm. These results suggest that the Ste4-LZ-SAM protein may recognize multiple binding sites on Byr2-SAM, indicating a new mode of oligomeric organization for SAM domains. The fact that high affinity binding occurs only with the addition of an oligomerization domain suggests that it may be necessary to include ancillary oligomerization modules when searching for binding partners of SAM domains.},
	keywords = {CRYSTAL-STRUCTURE, HUMAN LEUKEMIA, IDENTIFICATION, KINASE, LAC REPRESSOR, PROTEIN-KINASE, RECEPTOR, TEL, TRANSCRIPTION FACTOR, TYROSINE, YEAST},
	isbn = {0021-9258},
	url = {<Go to ISI>://000178662500069},
	author = {Ramachander, R. and Kim, C. A. and Phillips, M. L. and Mackereth, C. D. and Thanos, C. D. and McIntosh, L. P. and Bowie, J. U.}
}
@article {520,
	title = {Understanding nature{\textquoteright}s strategies for enzyme-catalyzed racemization and epimerization},
	journal = {Accounts of Chemical Research},
	volume = {35},
	number = {4},
	year = {2002},
	note = {ISI Document Delivery No.: 544TBTimes Cited: 65Cited Reference Count: 36},
	month = {Apr},
	pages = {237-246},
	type = {Review},
	abstract = {Epimerases and racemases are enzymes that catalyze the inversion of stereochemistry in biological molecules. In this article, three distinct examples are used to illustrate the wide range of chemical strategies employed during catalysis, and the diverse set of ancestors from which these enzymes have evolved. Glutamate racemase is an example of an enzyme that operates at an "activated" stereocenter (bearing a relatively acidic proton) and employs a nonstereospecific deprotonation/reprotonation mechanism. UDP-N-Acetylglucosamine 2-epimerase acts at an "unactivated" stereocenter and uses a mechanism involving a nonstereospecific elimination/addition of UDP. L-Ribulose phosphate 4-epimerase also acts at an unactivated stereocenter and uses a nonstereospecific retroaldol/aldol mechanism.},
	keywords = {ALDOLASE, CLASS-II, ESCHERICHIA-COLI, GLUTAMATE RACEMASE, IDENTIFICATION, L-FUCULOSE-1-PHOSPHATE, L-RIBULOSE-5-PHOSPHATE 4-EPIMERASE, MECHANISM, N-ACETYLGLUCOSAMINE 2-EPIMERASE, PHOSPHATE, RESIDUES},
	isbn = {0001-4842},
	url = {<Go to ISI>://000175175800005},
	author = {Tanner, M. E.}
}
@article {5085,
	title = {Biomethylation and bioaccumulation of arsenic(V) by marine alga Fucus gardneri},
	journal = {Applied Organometallic Chemistry},
	volume = {15},
	number = {6},
	year = {2001},
	note = {ISI Document Delivery No.: 435TUTimes Cited: 14Cited Reference Count: 23},
	month = {Jun},
	pages = {553-560},
	type = {Article},
	abstract = {The brown alga, Fucus gardneri, was collected from Vancouver Island, B,C,, Canada. Fucus samples were acclimated in seawater and then exposed to arsenic(V) in artificial seawater, all under axenic conditions. The arsenic species in the Fucus samples were extracted into 1:1 methanol-H2O and identified by using ion-pairing high-performance liquid chromatography coupled to inductively coupled plasma mass spectrometry (HPLC-ICP-MS), Anion-exchange HPLC-ICP-MS was used to identify the arsenic species in the growth medium. It was found that similar to 73\% of the original arsenosugars in the F, gardneri samples were lost during the acclimation period. Arsenite [As(III)] and dimethylarsenate [DMA] concentration increased in the Fucus samples after exposure to arsenate [As(V)], A small increase in the concentration of an arsenosugar was seen during this period, accompanied by a further decrease in the concentration of two other arsenosugars. The experiments provided very little evidence for the hypothesis that arsenosugars are produced by the macroalgae. Copyright (C) 2001 John Wiley \& Sons, Ltd.},
	keywords = {(ICP-MS), accumulation, ALGAE, arsenic, arsenite [As(III)], arsenosugar, biotransformation, chromatography (HPLC), dimethylarsenate [DMA], ENVIRONMENT, Fucus gardneri, high-performance liquid, IDENTIFICATION, inductively coupled plasma mass spectrometry},
	isbn = {0268-2605},
	url = {<Go to ISI>://000168897900015},
	author = {Granchinho, S. C. R. and Polishchuk, E. and Cullen, W. R. and Reimer, K. J.}
}
@article {5048,
	title = {Cdc4p, a contractile ring protein essential for cytokinesis in Schizosaccharomyces pombe, interacts with a phosphatidylinositol 4-kinase},
	journal = {Journal of Biological Chemistry},
	volume = {276},
	number = {8},
	year = {2001},
	note = {ISI Document Delivery No.: 404RUTimes Cited: 27Cited Reference Count: 35},
	month = {Feb},
	pages = {5932-5942},
	type = {Article},
	abstract = {The proposed function of Cdc4p, an essential contractile ring protein in Schizosaccharomyces pombe, is that of a myosin essential light chain. However, five conditionally lethal cdc4 alleles exhibit complementation in diploids. Such interallelic complementation is not readily explained if the sole function of Cde4p is that of a myosin essential light chain. Complementation of cdc4 alleles could occur only if different mutant forms can assemble into an active oligomeric complex or if Cdc4p has more than one essential function. To search for other proteins that may interact with Cdc4p, we performed a two-hybrid screen and identified two such candidates: one similar to Saccharomyces cerevisiae Vps27p and the other a putative phosphatidylinositol (PI) 4-kinase. finding of Cdc4p to the latter and to myosin heavy chain (Myo2p) was confirmed by immunosorbent assays. Deletion studies demonstrated interaction between the Cdc4p C-terminal domain and the PI 4-kinase C-terminal domain. Furthermore, interaction was abolished by the Cdc4p C-terminal domain point mutation, Gly(107) to Ser. This allele also causes failure of cytokinesis. Ectopic expression of the PI 4-kinase C-terminal domain caused cytokinesis defects that were most extreme in cells carrying the G107S allele. We suggest that Cdc4p plays multiple roles in cytokinesis and that interaction with a PI I-kinase may be important for contractile ring assembly and/or function.},
	keywords = {ACTOMYOSIN RING, BINDING, CELL-DIVISION CYCLE, F-ACTIN, FISSION YEAST, GENE, IDENTIFICATION, LIGHT-CHAIN, LOCALIZATION, MYOSIN HEAVY-CHAIN},
	isbn = {0021-9258},
	url = {<Go to ISI>://000167115100071},
	author = {Desautels, M. and Den Haese, J. P. and Slupsky, C. M. and McIntosh, L. P. and Hemmingsen, S. M.}
}
@article {5189,
	title = {Collision-induced dissociation of bradykinin ions in the interface region of an ESI-MS},
	journal = {Journal of the American Society for Mass Spectrometry},
	volume = {12},
	number = {7},
	year = {2001},
	note = {ISI Document Delivery No.: 447HHTimes Cited: 17Cited Reference Count: 42},
	month = {Jul},
	pages = {772-779},
	type = {Article},
	abstract = {By applying different electric field strengths to the orifice-skimmer region of an electrospray ionization mass spectrometer, the rate of dissociation can be varied based on the amount of infernal energy acquired by an ion through collisions: with the curtain gas molecules. Both the Arrhenius equation and Rice-Ramsperger-Kassel (RRK) theory can be used to predict the rate of dissociation of internally excited molecules. A previously determined model for collision-induced dissociation is tested by comparison of predicted and experimentally observed orifice-skimmer potential differences for dissociation of ions. The rate of collision-induced dissociation of bradykinin ions is determined by monitoring the fragments produced in a mass spectrometer. The semi-quantitative model is found to yield effective predictions when accurate Arrhenius and RRK parameters are utilized. (C) 2001 American Society for Mass Spectrometry.},
	keywords = {ACTIVATION, CYTOCHROME-C, ELECTROSPRAY-IONIZATION, GAS-PHASE, IDENTIFICATION, INFRARED RADIATIVE DISSOCIATION, IONIZATION MASS-SPECTROMETRY, MOLECULES, PEPTIDES, PROTEIN IONS},
	isbn = {1044-0305},
	url = {<Go to ISI>://000169565500002},
	author = {Schneider, B. B. and Douglas, D. J. and Chen, D. D. Y.}
}
@article {4879,
	title = {The adsorption of microcystin-LR by natural clay particles},
	journal = {Toxicon},
	volume = {38},
	number = {2},
	year = {2000},
	note = {ISI Document Delivery No.: 257VLTimes Cited: 40Cited Reference Count: 35},
	month = {Feb},
	pages = {303-308},
	type = {Article},
	abstract = {The microcystin cyanobacterial hepatotoxins represent an increasingly severe global health hazard. Sines microcystins are found world wide in drinking water reservoirs concern about the impact on human health has prompted investigations into remedial water treatment methods. This preliminary study investigates the scavenging from water of microcystin-LR by fine-grained particles known to have a high concentration of the clay minerals kaolinite and montmorillonite. The results show that more than 81\% of microcystin-LR can be removed from water by clay material. Thus, microcystin-LR is indeed scavenged from water bodies by fine-grained particles and that this property may offer an effective method of stripping these toxins from drinking water supplies. (C) 1999 Elsevier Science Ltd. All rights reserved.},
	keywords = {BLOOM, cyanobacteria, DECOMPOSITION, DIARRHETIC SHELLFISH TOXINS, ENVIRONMENT, IDENTIFICATION, OKADAIC ACID, OSCILLATORIA-AGARDHII, PROTEIN PHOSPHATASE INHIBITORS, TUMOR PROMOTION},
	isbn = {0041-0101},
	url = {<Go to ISI>://000083803000016},
	author = {Morris, R. J. and Williams, D. E. and Luu, H. A. and Holmes, C. F. B. and Andersen, R. J. and Calvert, S. E.}
}
@article {4924,
	title = {Collision-induced dissociation of ions within the orifice-skimmer region of an electrospray mass spectrometer},
	journal = {Analytical Chemistry},
	volume = {72},
	number = {4},
	year = {2000},
	note = {ISI Document Delivery No.: 285HETimes Cited: 38Cited Reference Count: 33},
	month = {Feb},
	pages = {791-799},
	type = {Article},
	abstract = {An equation was derived to describe the variation of the gas number density within the region between the orifice and the skimmer of an electrospray ionization mass spectrometer. The equation was used to develop a semiquantitative model to predict the value of orifice voltages that lead to ion fragmentation within this region. This model made it possible to predict the types of solvent adducts observed for analytes at various orifice voltages. In addition, it is shown that a small number of high-energy collisions is equally effective for collision-induced dissociation as compared to a large number of low-energy collisions. Finally, this model is tested with different background electrolyte solutions and a different electrospray mass spectrometer. It is demonstrated that controlled fragmentation studies can be performed on single-quadrupole mass spectrometers, and the proposed model gives a reasonable description of the fragmentation process in both spectrometers.},
	keywords = {capillary electrophoresis, CYTOCHROME-C, DYNAMICS, IDENTIFICATION, INTERFACE, IONIZATION, LIQUID-CHROMATOGRAPHY, PROTEINS, SENSITIVITY, SEPARATION},
	isbn = {0003-2700},
	url = {<Go to ISI>://000085383000019},
	author = {Schneider, B. B. and Chen, D. D. Y.}
}
@article {4593,
	title = {Arsenic speciation in scallops},
	journal = {Marine Chemistry},
	volume = {66},
	number = {1-2},
	year = {1999},
	note = {ISI Document Delivery No.: 214FQTimes Cited: 42Cited Reference Count: 33},
	month = {Jul},
	pages = {81-89},
	type = {Article},
	abstract = {The arsenic species present in the muscle and the gonad of scallops collected near Newfoundland were characterized by using high performance liquid chromatography-inductively coupled plasma-mass spectrometry (HPLC-ICP-MS). The adductor muscle of the scallops (2.1-9.4 mu g As g(-1)) contains arsenobetaine (AsB) as the major water-soluble arsenic compound. The gonads of the scallops (7.3-44.1 mu g As g(-1)) contain dimethylarsinoylriboside derivatives as the major arsenic compound, as well as lower amounts of AsB. No inorganic arsenic species was detected in the sample extracts indicating that consumption of the scallops poses little human risk. (C) 1999 Elsevier Science B.V. All rights reserved.},
	keywords = {arsenic, arsenobetaine, arsenosugar, CONTAINING RIBOFURANOSIDES, HPLC, ICP-MS, IDENTIFICATION, SAMPLES, scallops, SEAWEED, SPECIATION},
	isbn = {0304-4203},
	url = {<Go to ISI>://000081318300004},
	author = {Lai, V. W. M. and Cullen, W. R. and Ray, S.}
}
@article {4646,
	title = {Domain movement in gelsolin: A calcium-activated switch},
	journal = {Science},
	volume = {286},
	number = {5446},
	year = {1999},
	note = {ISI Document Delivery No.: 261HHTimes Cited: 94Cited Reference Count: 18},
	month = {Dec},
	pages = {1939-1942},
	type = {Article},
	abstract = {The actin-binding protein gelsolin is involved in remodeling the actin cytoskeleton during growth-factor signaling, apoptosis, cytokinesis, and cell movement. Calcium-activated gelsolin severs and caps actin filaments, The 3.4 angstrom x-ray structure of the carboxyl-terminal half of gelsolin (G4-G6) in complex with actin reveals the basis for gelsolin activation. Calcium binding induces a conformational rearrangement in which domain G6 is flipped over and translated by about 40 angstroms relative to G4 and G5. The structural reorganization tears apart the continuous beta sheet core of G4 and G6. This exposes the actin-binding site on G4, enabling severing and capping of actin filaments to proceed.},
	keywords = {actin, BINDING-SITE, COMPLEX, FILAMENT, IDENTIFICATION, PLASMA GELSOLIN},
	isbn = {0036-8075},
	url = {<Go to ISI>://000084003400047},
	author = {Robinson, R. C. and Mejillano, M. and Le, V. P. and Burtnick, L. D. and Yin, H. L. and Choe, S.}
}
@article {4667,
	title = {Sugar ring distortion in the glycosyl-enzyme intermediate of a family G/11 xylanase},
	journal = {Biochemistry},
	volume = {38},
	number = {17},
	year = {1999},
	note = {ISI Document Delivery No.: 193YMTimes Cited: 122Cited Reference Count: 50},
	month = {Apr},
	pages = {5346-5354},
	type = {Article},
	abstract = {The 1.8 Angstrom resolution structure of the glycosyl-enzyme intermediate formed on the retaining beta-1,4-xylanase from Bacillus circulans has been determined using X-ray crystallographic techniques. The 2-fluoro-xylose residue bound in the -1 subsite adopts a B-2,B-5 (boat) conformation, allowing atoms C5, O5, C1, and C2 of the sugar to achieve coplanarity as required at the oxocarbenium ion-like transition states of the double-displacement catalytic mechanism. Comparison of this structure to that of a mutant of this same enzyme noncovalently complexed with xylotetraose [Wakarchuk et al. (1994) Protein Sci. 3, 467-475] reveals a number of differences beyond the distortion of the sugar moiety. Most notably, a bifurcated hydrogen bond interaction is formed in the glycosyl-enzyme intermediate involving H-eta of Tyr69, the endocyclic oxygen (O5) of the xylose residue in the -1 subsite, and O-epsilon 2 of the catalytic nucleophile, Glu78. To gain additional understanding of the role of Tyr69 at the active site of this enzyme, we also determined the 1.5 Angstrom resolution structure of the catalytically inactive Tyr69Phe mutant. Interestingly, no significant structural perturbation due to the loss of the phenolic group is observed. These results suggest that the interactions involving the phenolic group of Tyr69, O5 of the proximal saccharide, and Glu78 O-epsilon 2 important for the catalytic mechanism of this enzyme, and it is proposed that, through charge redistribution, these interactions serve to stabilize the oxocarbenium-like ion of the transition state. Studies of the covalent glycosyl-enzyme intermediate of this xylanase also provide insight into specificity, as contacts with C5 of the xylose moiety exclude sugars with hydroxymethyl substituents, and the mechanism of catalysis, including aspects of stereoelectronic theory as applied to glycoside hydrolysis.},
	keywords = {ACTIVE-SITE RESIDUES, BACILLUS-CIRCULANS XYLANASE, beta-glucosidase, CELLULOMONAS-FIMI, glycosidase, IDENTIFICATION, LEAVING GROUP, MECHANISM, REACTION COORDINATE, TRICHODERMA-REESEI},
	isbn = {0006-2960},
	url = {<Go to ISI>://000080165400009},
	author = {Sidhu, G. and Withers, S. G. and Nguyen, N. T. and McIntosh, L. P. and Ziser, L. and Brayer, G. D.}
}
@article {4447,
	title = {Pre-steady state kinetic analysis of an enzymatic reaction monitored by time-resolved electrospray ionization mass spectrometry},
	journal = {Biochemistry},
	volume = {37},
	number = {21},
	year = {1998},
	note = {ISI Document Delivery No.: ZR717Times Cited: 73Cited Reference Count: 53},
	month = {May},
	pages = {7664-7669},
	type = {Article},
	abstract = {For the first time, the new technique of time-resolved electrospray ionization mass spectrometry (ESI-MS) has been used to accurately measure the pre-steady state kinetics of an enzymatic reaction by monitoring a transient enzyme intermediate. The enzyme used to illustrate this approach, Bacillus circulans xylanase, is a retaining glycosidase that hydrolyzes xylan or beta-xylobiosides through a double-displacement mechanism involving a covalent xylobiosyl-enzyme intermediate. A low steady state level of this intermediate formed during the hydrolysis of 2,5-dinitrophenyl beta-D-xylobioside was detected by time-resolved ESI-MS. The low concentration of this intermediate and its rate of formation did not permit pre-steady state kinetic analysis. By contrast, the covalent intermediate accumulates fully when the Tyr80Phe mutant hydrolyzes the same substrate. Using time-resolved ESI-MS, the pre-steady state kinetic parameters for the formation of the covalent intermediate in the mutant xylanase have been determined. The kinetic data are in agreement with those determined by monitoring the release of 2,5-dinitrophenol with stopped-flow W-vis spectroscopy. This demonstrates that time-resolved ESI-MS can be used to accurately monitor the pre-steady state kinetics of enzymatic reactions, with the advantage of identifying transient enzyme intermediates by their mass.},
	keywords = {ACTIVE-SITE NUCLEOPHILE, AMINO-ACID, BACILLUS-CIRCULANS XYLANASE, beta-glucosidase, CELLULASES, CYTOCHROME-C, GAS-PHASE, IDENTIFICATION, inhibitors, MECHANISMS},
	isbn = {0006-2960},
	url = {<Go to ISI>://000074006700002},
	author = {Zechel, D. L. and Konermann, L. and Withers, S. G. and Douglas, D. J.}
}
@article {4158,
	title = {Bioaccumulation and clearance of microcystins from salt water, mussels, Mytilus edulis, and in vivo evidence for covalently bound microcystins in mussel tissues},
	journal = {Toxicon},
	volume = {35},
	number = {11},
	year = {1997},
	note = {ISI Document Delivery No.: YM145Times Cited: 73Cited Reference Count: 48},
	month = {Nov},
	pages = {1617-1625},
	type = {Article},
	abstract = {Over a period of 3 days saltwater mussels, Mytilus edulis, were fed a cyanobacteria, Microcystis aeruginosa, that contained a high concentration of microcystins, The mussels were killed on a periodic basis over the course of 2 months, Mussels were also collected at two sites were high levels of microcystins in tissues had been noted. A strategy based on the chemically unique nature of the C-20 beta-amino acid, (2S,3S,8S,9S)-3-amino-9-methoxy-2,6,8-trimethyl-10-phenyldeca-4,6-dienoi c acid (Adda), portion of the microcystins was used in conjunction with a protein phosphatase (PPase) assay to analyse for both covalently bound microcystins and free microcystins in the mussel tissues, The mussel PPase assay results were compared with the Lemieux oxidation gas chromatography-mass spectrometry (GCMS) analysis. Less than 0.1\% of the total microcystin burden in the mussel tissue was found to be extractable with MeOH. Thus, direct evidence was provided for the existence of covalently bound microcystins in mussel tissues in vivo. The mussels rapidly cleared the covalently bound microcystins when transferred to untreated seawater. Within 4 days the total microcystin burden dropped from a high of 336.9 (+/- 45.8) mu g/g wet tissue to 11.3 (+/- 2.6) mu g/g. After 4 days postexposure until completion of the experiment the total levels remained below the detection limits of the GCMS method, The levels of free microcystins, extracted with MeOH and detected by the PPase assay, fell from 204 ng/g wet tissue to a residual 14 ng/g over a 53 day postexposure period. Presumably the bound microcystin present in the mussel tissue exists as a covalent complex with the PP-1 and PP-2A enzymes. We conclude that in any shellfish monitoring program it is the total tissue microcystin burden that needs to be considered. (C) 1997 Elsevier Science Ltd.},
	keywords = {AERUGINOSA, BLUE-GREEN-ALGAE, cyanobacteria, DIARRHETIC SHELLFISH TOXINS, IDENTIFICATION, LR, OKADAIC ACID, PEPTIDE TOXIN, PROTEIN PHOSPHATASE INHIBITORS, TUMOR PROMOTION},
	isbn = {0041-0101},
	url = {<Go to ISI>://000071033700005},
	author = {Williams, D. E. and Dawe, S. C. and Kent, M. L. and Andersen, R. J. and Craig, M. and Holmes, C. F. B.}
}
@article {4156,
	title = {C-14-Labeled microcystin-LR administered to Atlantic salmon via intraperitoneal injection provides in vivo evidence for covalent binding of microcystin-LR in salmon livers},
	journal = {Toxicon},
	volume = {35},
	number = {6},
	year = {1997},
	note = {ISI Document Delivery No.: XG731Times Cited: 32Cited Reference Count: 18},
	month = {Jun},
	pages = {985-989},
	type = {Article},
	abstract = {The tissue distribution and clearance of radiolabeled microcystin-LR administered to Atlantic salmon via i.p. injection has been re-examined using uniformly C-14-labeled toxin, Significant differences were found to exist between these results and those obtained when fish received an i.p. injection of tritium-labeled dihydromicrocystin-LR. In addition, MeOH liver extracts were assayed by both phosphatase assay and C-14 counts and the results compared with the total levels of incorporation determined by digestion and subsequent C-14 counting of the same liver tissues. An attempt to investigate the metabolism and to document the putative products was also undertaken. It was found that microcystin-LR was extensively metabolized to compounds that are more polar than the parent compound. (C) 1997 Elsevier Science Ltd.},
	keywords = {biotransformation, CHROMATOGRAPHY, DIARRHETIC SHELLFISH TOXINS, DISEASE, IDENTIFICATION, INHIBITOR, POTENT, PROTEIN PHOSPHATASE, TISSUE DISTRIBUTION, TYPE-1},
	isbn = {0041-0101},
	url = {<Go to ISI>://A1997XG73100017},
	author = {Williams, D. E. and Craig, M. and Dawe, S. C. and Kent, M. L. and Andersen, R. J. and Holmes, C. F. B.}
}
@article {4043,
	title = {The characterization of arsenosugars in commercially available algal products including a Nostoc species of terrestrial origin},
	journal = {Applied Organometallic Chemistry},
	volume = {11},
	number = {10-11},
	year = {1997},
	note = {ISI Document Delivery No.: YB269Times Cited: 77Cited Reference Count: 28},
	month = {Oct-Nov},
	pages = {797-803},
	type = {Article},
	abstract = {The arsenic species present in a range of commercially available dried-algal food products were characterized by HPLC-ICP-MS, The products of marine origin contain up to four dimethylarsinylribosides (1) in the 8-49 ppm range and some also contain dimethylarsinic acid (DMAA). These species are easily extracted and account for most of the arsenic burden. One sample of a freshwater alga Nostoc sp, was found to contain a lower concentration of arsenic, 3 ppm, and only 34\% of this was extractable, The extract representing 1 ppm of arsenic contained one of the arsenosugars 1 found in the marine samples (93\%), the rest being DMAA, This is the first report of the identification of an arsenosugar from an organism of terrestrial origin, The implications of this result in connection with the global arsenic cycle are discussed. (C) 1997 John Wiley \& Sons, Ltd.},
	keywords = {(ICP-MS), ACID, ALGAE, arsenic, ARSENIC-CONTAINING RIBOFURANOSIDES, arsenobetaine, arsenosugar, ATOMIC-ABSORPTION SPECTROMETRY, chromatography (HPLC), high-performance liquid, IDENTIFICATION, inductively coupled plasma-mass spectrometry, SEAWEED, SPECIATION},
	isbn = {0268-2605},
	url = {<Go to ISI>://A1997YB26900005},
	author = {Lai, V. W. M. and Cullen, W. R. and Harrington, C. F. and Reimer, K. J.}
}
@article {3920,
	title = {The crystal structure of plasma gelsolin: Implications for actin severing, capping, and nucleation},
	journal = {Cell},
	volume = {90},
	number = {4},
	year = {1997},
	note = {ISI Document Delivery No.: XT066Times Cited: 164Cited Reference Count: 50},
	month = {Aug},
	pages = {661-670},
	type = {Article},
	abstract = {The structure of gelsolin has been determined by crystallography and comprises six structurally related domains that, in a Ca2+-free environment, pack together to form a compact globular structure in which the putative actin-binding sequences are not sufficiently exposed to enable binding to occur. We propose that binding Ca2+ can release the connections that join the N- and C-terminal halves of gelsolin, enabling each half to bind actin relatively independently. Domain shifts are proposed in response to Ca2+ as bases for models of how gelsolin acts to sever, cap, or nucleate F-actin filaments. The structure also invites discussion of polyphosphoinositide binding to segment 2 and suggests how mutation at Asp-187 could initiate a series of events that lead to deposition of amyloid plaques, as observed in victims of familial amyloidosis (Finnish type).},
	keywords = {AMYLOIDOSIS, BINDING DOMAIN, calcium, DEFINITION, F-ACTIN, FILAMENT, IDENTIFICATION, PROTEIN, SEQUENCE, VILLIN},
	isbn = {0092-8674},
	url = {<Go to ISI>://A1997XT06600010},
	author = {Burtnick, L. D. and Koepf, E. K. and Grimes, J. and Jones, E. Y. and Stuart, D. I. and McLaughlin, P. J. and Robinson, R. C.}
}
@article {4069,
	title = {Design and synthesis of 2{\textquoteright}-deoxy-2{\textquoteright}-fluorodisaccharides as mechanism-based glycosidase inhibitors that exploit aglycon specificity},
	journal = {Journal of the American Chemical Society},
	volume = {119},
	number = {25},
	year = {1997},
	note = {ISI Document Delivery No.: XG882Times Cited: 37Cited Reference Count: 23},
	month = {Jun},
	pages = {5792-5797},
	type = {Article},
	abstract = {Stable, aglycon-specific inactivators of glycosidases have considerable potential as fools in the study of mechanisms of oligosaccharide processing, and possibly as avenues toward new therapeutics. Glycosidases for which the rate-determining step with the natural substrate is the hydrolysis of the glycosyl-enzyme intermediate are shown to be inactivated by the 2{\textquoteright}-deoxy-2{\textquoteright}-fluoro derivative of this substrate. Thus Agrobacterium faecalis beta-glucosidase is inactivated by 2{\textquoteright}-deoxy-2{\textquoteright}-fluorocellobiose according to inactivation parameters of k(i) = 0.018 min(-1) and K-i = 20 mM. Inactivation is shown to occur via the accumulation of the same 2-deoxy-2-fluoroglycosyl-enzyme intermediate as that formed using activated 2-deoxy-2-fluoroglycosides by identification of the labeled peptide in proteolytic digests. Thus, interactions between the enzyme and the sugar aglycon provide sufficient transition state stabilization to allow formation and trapping of the glycosyl-enzyme. beta-Glucocerebrosidase, a beta-glucosidase specific for hydrolysis of glucocerebrosides, is not inactivated by 2{\textquoteright}-deoxy-2{\textquoteright}-fluorocellobiose, thereby demonstrating the aglycon specificity of this class of inactivator.},
	keywords = {ACTIVE-SITE NUCLEOPHILE, beta-glucosidase, GALACTOSIDASE, IDENTIFICATION, residue, TANDEM MASS-SPECTROMETRY},
	isbn = {0002-7863},
	url = {<Go to ISI>://A1997XG88200003},
	author = {McCarter, J. D. and Yeung, W. and Chow, J. and Dolphin, D. and Withers, S. G.}
}
@article {3640,
	title = {Molecular mechanisms underlying the interaction of motuporin and microycystins with type-1 and type-2A protein phosphatases},
	journal = {Biochemistry and Cell Biology-Biochimie Et Biologie Cellulaire},
	volume = {74},
	number = {4},
	year = {1996},
	note = {ISI Document Delivery No.: VX367Times Cited: 61Cited Reference Count: 35},
	pages = {569-578},
	type = {Article},
	abstract = {Heptapeptide microcystin and pentapeptide motuporin (nodularin-V) are equipotent inhibitors of type-1 and type-2A protein phosphatase catalytic subunits (PP-1c and PP-2Ac). Herein we describe elucidation of the molecular mechanisms involved in the interaction of these structurally similar hepatotoxins with PP-1c/PP-2Ac and identification of an important functional difference between their mode of interaction with these enzymes. Microcystin-LR, microcystin-LA and microcystin-LL were found to interact with PP-2Ac and PP-1c by a two-step mechanism involving rapid binding and inactivation of the protein phosphatase (PPase) catalytic subunit, followed by a slower covalent interaction (within hours). Covalent adducts comprising PPase-toxin complexes were separated from free PPase by C-18 reverse-phase liquid chromatography, thus allowing the time course of covalent adduct formation to be quantitated. In contrast to microcystins, motuporin (nodularin-V) and nodularin-R were unable to form covalent complexes with either PP-1c or PP-2Ac even after 96 h incubation. Specific reduction of microcystin-LA to dihydromicrocystin-LA abolished the ability of the toxin to form a covalent adduct with PP-2Ac. Specific methyl esterification of the single Glu residue in microcystin-LR rendered this toxin inactive as a PPase inhibitor and abolished subsequent formation of a covalent adduct. Our data indicate that inactivation of PP-2Ac/PP-1c by microcystins precedes covalent modification of the PPases via a Michael addition reaction between a nucleophilic phosphatase residue and Mdha in the heptapeptide toxin. In contrast, following rapid inactivation of PP-2Ac/PP-1c by motuporin, the equivalent N-methyldehydrobutyrine residue in this toxin is unreactive and does not form a covalent bond with the PPases. These results are consistent with structural data for (i) the NMR solution structures of microcystin-LR and motuporin, which indicate a striking difference in the relative positions of their corresponding dehydroamino acids in the toxin peptide backbone, and (ii) X-ray crystallographic data on an inactive complex between PP-1c and microcystin-LR, which show a covalent bond between Cys-273 and the bound toxin.},
	keywords = {BLUE-GREEN-ALGAE, CATALYTIC SUBUNIT, cyanobacteria, IDENTIFICATION, MICROCYSTIN-LR, microcystins, motuporin, nodularin, OKADAIC ACID, PHOSPHORYLATION, POTENT INHIBITOR, PROTEIN, PROTEIN PHOSPHATASES, RAT-LIVER, TOXINS},
	isbn = {0829-8211},
	url = {<Go to ISI>://A1996VX36700017},
	author = {Craig, M. and Luu, H. A. and McCready, T. L. and Williams, D. and Andersen, R. J. and Holmes, C. F. B.}
}
@article {3762,
	title = {The pK(a) of the general acid/base carboxyl group of a glycosidase cycles during catalysis: A C-13-NMR study of Bacillus circuluns xylanase},
	journal = {Biochemistry},
	volume = {35},
	number = {31},
	year = {1996},
	note = {ISI Document Delivery No.: VB211Times Cited: 149Cited Reference Count: 43},
	month = {Aug},
	pages = {9958-9966},
	type = {Article},
	abstract = {The 20 kDa xylanase from Bacillus circulans carries out hydrolysis of xylan via a two-step mechanism involving a covalent glycosyl-enzyme intermediate. In this double-displacement reaction, Glu78 functions as a nucleophile to form the intermediate, while Glu172 acts as a general acid catalyst during glycosylation, protonating the departing aglycone, and then as a general base during deglycosylation, deprotonating the attacking water, The dual role of Glu172 places specific demands upon its ionization states and hence pK(a) values. C-13-NMR titrations of xylanase, labeled with [delta-C-13]glutamic acid, have revealed pK(a) values of 4.6 and 6.7 for Glu78 and Glu172, respectively. These agree well with the apparent pK(a) values obtained from a study of the pH dependence of k(cat)/K-m and demonstrate that, at the enzyme{\textquoteright}s pH optimum of 5.7, the nucleophile Glu78 is deprotonated and the general acid Glu172 initially protonated. Remarkably, the pK(a) for Glu172 drops to 4.2 in a trapped covalent glycosyl-enzyme intermediate, formed by reaction with 2{\textquoteright},4{\textquoteright}-dinitrophenyl 2-deoxy-2-fluoro-beta-xylobioside [Miao et al. (1994) Biochemistry 33, 7027-7032], A similar pK(a) is measured for Glu172 when a glutamine is present at position 78. This large decrease in pK(a) of similar to 2.5 units is consistent with the role of Glu172 as a general base catalyst in the deglycosylation step and appears to be a consequence of both reduced electrostatic repulsion due to neutralization of Glu78 and a conformational change in the protein. Such {\textquoteright}{\textquoteright}pK(a) cycling{\textquoteright}{\textquoteright} during catalysis is likely to be a common phenomenon in glycosidases.},
	keywords = {ACTIVE-SITE RESIDUES, AMINO-ACIDS, beta-glucosidase, ELECTROSTATIC INTERACTIONS, ESCHERICHIA-COLI, IDENTIFICATION, LYSOZYME, MECHANISMS, NUCLEAR-MAGNETIC-RESONANCE, PROTEINS},
	isbn = {0006-2960},
	url = {<Go to ISI>://A1996VB21100003},
	author = {McIntosh, L. P. and Hand, G. and Johnson, P. E. and Joshi, M. D. and Korner, M. and Plesniak, L. A. and Ziser, L. and Wakarchuk, W. W. and Withers, S. G.}
}
@article {3552,
	title = {TISSUE DISTRIBUTION AND CLEARANCE OF TRITIUM-LABELED DIHYDROMICROCYSTIN-LR EPIMERS ADMINISTERED TO ATLANTIC SALMON VIA INTRAPERITONEAL INJECTION},
	journal = {Toxicon},
	volume = {33},
	number = {2},
	year = {1995},
	note = {ISI Document Delivery No.: QQ042Times Cited: 33Cited Reference Count: 20},
	month = {Feb},
	pages = {125-131},
	type = {Article},
	abstract = {The two epimers of [H-3]dihydromicrocystin-LR (spec. act. 32.6 mu Ci/mu mole) were synthesized by reduction of microcystin-LR, a cyclic heptapeptide hepatotoxin, with sodium boro[H-3]hydride. In Atlantic salmon, following an i.p. injection of the epimers (0.1 mg of toxin/100 g), the toxins were; after 2 hr, concentrated in the liver and pyloric caeca and intestine; after 5 and 22 hr, concentrated in the liver; and after 46 hr concentrated in the liver and kidney. The maximum concentration in the liver, 4.9 +/- 0.5\% of the injected dose, was observed at 5 hr. At 46 hr the incorporation of tritium in the liver was 2.4\%. The total whole body incorporation of tritium label at 2, 5, 22 and 46 hr was 67.9 +/- 7.3\%, 78.4 +/- 3.1\%, 54.5 +/- 6.6\% and 12.2\%, respectively. The per cent levels of incorporation are significantly lower and the clearance rates are significantly higher than those observed in mice. The ratio of relative concentrations of radiolabel observed in the livers and flesh indicates that extremely low levels of microcystin-LR would be present in the flesh of fish afflicted with {\textquoteright}netpen liver disease{\textquoteright}. Coupled with further evidence, it is suggested that the consumption of Atlantic salmon suffering from {\textquoteright}netpen liver disease{\textquoteright} does not represent a potential human health hazard.},
	keywords = {AERUGINOSA, DIARRHETIC SHELLFISH TOXINS, HEPATOTOXINS, IDENTIFICATION, MICROCYSTIN-LR, NETPEN LIVER-DISEASE, TOXICITY},
	isbn = {0041-0101},
	url = {<Go to ISI>://A1995QQ04200002},
	author = {Williams, D. E. and Kent, M. L. and Andersen, R. J. and Klix, H. and Holmes, C. F. B.}
}
@article {3000,
	title = {BIOACCUMULATION AND EXCRETION OF ARSENIC COMPOUNDS BY A MARINE UNICELLULAR ALGA, POLYPHYSA-PENICULUS},
	journal = {Applied Organometallic Chemistry},
	volume = {8},
	number = {4},
	year = {1994},
	note = {ISI Document Delivery No.: PD643Times Cited: 27Cited Reference Count: 43},
	month = {Jul},
	pages = {313-324},
	type = {Article},
	abstract = {Polyphysa peniculus was grown in artificial sea-water in the presence of arsenate, arsenite, monomethylarsonate and dimethylarsinic acid. The separation and identification of some of the arsenic species produced in the cells as well as in the growth medium were achieved by using hydride generation-gas chromatography-atomic absorption spectrometry methodology. Arsenite and dimethylarsinate were detected following incubation with arsenate. When the alga was treated with arsenite, dimethylarsinate was the major metabolite in the cells and in the growth medium; trace amounts of monomethylarsonate were also detected in the cells. With monomethylarsonate as a substrate, the metabolite is dimethylarsinate. Polyphysa peniculus did not metabolize dimethylarsinic acid when it was used as a substrate. Significant amounts of more complex arsenic species, such as arsenosugars, were not observed in the cells or medium on the evidence of flow injection-microwave digestion-hydride generation-atomic absorption spectrometry methodology. Transfer of the exposed cells to fresh medium caused release of most cell-associated arsenicals to the surrounding environment.},
	keywords = {ARSENIC BIOACCUMULATION, ARSENIC METYLATION, arsenic species, ARSENIC UPTAKE, COMPOUNDS, CONTAINING RIBOFURANOSIDES, ENVIRONMENT, IDENTIFICATION, KELP ECKLONIA-RADIATA, METABOLISM, METHYLATION, NON-REDUCIBLE ARSENICALS, ORGANOARSENIC, PHYTOPLANKTON, POLYPHYSA-PENICULUS, RIVER BEAULIEU, SPECIATION},
	isbn = {0268-2605},
	url = {<Go to ISI>://A1994PD64300004},
	author = {Cullen, W. R. and Harrison, L. G. and Li, H. and Hewitt, G.}
}
@article {3139,
	title = {EVALUATION OF MATRIX-ASSISTED LASER DESORPTION/IONIZATION TIME-OF-FLIGHT MASS-SPECTROMETRY FOR THE ANALYSIS OF ORGANOARSENIC COMPOUNDS OF ENVIRONMENTAL INTEREST},
	journal = {Biological Mass Spectrometry},
	volume = {23},
	number = {12},
	year = {1994},
	note = {ISI Document Delivery No.: PX594Times Cited: 9Cited Reference Count: 45},
	month = {Dec},
	pages = {749-755},
	type = {Article},
	abstract = {Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) was investigated for arsenic speciation of compounds of environmental interest. It is a very sensitive mass spectrometric technique which can detect as little as 0.3 ng of arsenic or 4 pmol of the arsenical under investigation. This feature suggests that the method could be used for the identification of minor arsenic components in environmental samples, Additional advantages of the technique are its capability of providing molecular ions as well as fragment ions for a variety of arsenicals, and allowing for a certain degree of control in compound fragmentation, by adjusting the N-2 laser power. Quantitative analysis by MALDI-TOF-MS is still considered a highly unreliable procedure since many variables associated with sample preparation and analytical procedure can seriously affect the results.},
	keywords = {arsenic, arsenobetaine, ARSENOCHOLINE, COMPOUNDS, CONFIRMATION, desorption, FAST ATOM BOMBARDMENT, IDENTIFICATION, OLIGOSACCHARIDES, PERFORMANCE LIQUID-CHROMATOGRAPHY, SPECIATION},
	isbn = {1052-9306},
	url = {<Go to ISI>://A1994PX59400005},
	author = {Pergantis, S. A. and Cullen, W. R. and Eigendorf, G. K.}
}
@article {3003,
	title = {THE METHYLATION OF ARSENATE BY A MARINE ALGA POLYPHYSA-PENICULUS IN THE PRESENCE OF L-METHIONINE-METHYL-D(3)},
	journal = {Chemosphere},
	volume = {28},
	number = {5},
	year = {1994},
	note = {ISI Document Delivery No.: NC959Times Cited: 13Cited Reference Count: 39},
	month = {Mar},
	pages = {1009-1019},
	type = {Article},
	abstract = {Polyphysa peniculus growing in artificial seawater methylates arsenate to produce a dimethylarsenic derivative, probably dimethylarsinate. When L-methionine-methyl-d3 is added to the culture the CD3 label is incorporated intact in the dimethylarsenic compound to a considerable extent, indicating that S-adenosylmethionine, or some related sulphonium compound, is involved in the biological methylation. Conclusive evidence of the CD3 incorporation was provided by using a specially developed hydride generation-gas chromatography-mass spectrometry methodology.},
	keywords = {ALGAE, arsenic, COMPOUNDS, CONTAINING RIBOFURANOSIDES, ENVIRONMENT, GENERATION GAS CHROMATOGRAPHY MASS SPECTROMETRY (HG-GC-MS), hydride, IDENTIFICATION, KELP ECKLONIA-RADIATA, L-METHIONINE-METHYL-D(3), METHYLARSENIC COMPOUNDS, METHYLATION, NATURAL-WATERS, ORGANOARSENIC, REDUCTION, SPECIATION, SPECTROMETRY},
	isbn = {0045-6535},
	url = {<Go to ISI>://A1994NC95900016},
	author = {Cullen, W. R. and Li, H. and Pergantis, S. A. and Eigendorf, G. K. and Harrison, L. G.}
}
@article {3092,
	title = {SPECIATION OF ARSENIC COMPOUNDS BY HPLC WITH HYDRIDE GENERATION ATOMIC-ABSORPTION SPECTROMETRY AND INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY DETECTION},
	journal = {Talanta},
	volume = {41},
	number = {4},
	year = {1994},
	note = {ISI Document Delivery No.: NJ813Times Cited: 94Cited Reference Count: 45},
	month = {Apr},
	pages = {495-502},
	type = {Article},
	abstract = {An arsenic specific detection system utilizing on-line microwave digestion and hydride generation atomic absorption spectrometry (MD/HGAAS) is described for arsenic speciation by using high performance liquid chromatography (HPLC). Both ion exchange chromatography and ion pair chromatography have been studied for the separation of arsenite, arsenate, monomethylarsonic acid (MMAA), dimethylarsinic acid (DMAA), and arsenobetaine (AB). When the commonly used mobile phases, phosphate and carbonate buffers at pH 7.5, are used on an anion exchange column, arsenite and AB co-elute. However, selective determination of these two arsenic compounds can be achieved by using the new detection system. Partial separation between arsenite and AB can be achieved by increasing the mobile phase pH to 10.3 and by using a polymer based anion exchange column. The detection limit obtained by using anion exchange chromatography with MD/HGAAS detection is approximately 10 ng/ml (or 200 pg for a 20-mul sample injection) for arsenite, DMAA and AB, 15 ng/ml (or 300 pg) for MMAA, and 20 ng/ml (or 400 pg) for arsenate. Complete separation of the five arsenic compounds is achieved on a reversed phase C18 column by using sodium heptanesulfonate as ion pair reagent. Comparable resolution between chromatographic peaks is obtained by using MD/HGAAS detection and inductively coupled plasma mass spectrometry (ICPMS) detection.},
	keywords = {ELEMENT-SPECIFIC DETECTOR, IDENTIFICATION, ION CHROMATOGRAPHY, MUSCLE, ORGANOARSENIC COMPOUNDS, PERFORMANCE LIQUID-CHROMATOGRAPHY, QUANTITATION, REFERENCE MATERIAL, SEPARATION, TRACE-ELEMENTS, WATER},
	isbn = {0039-9140},
	url = {<Go to ISI>://A1994NJ81300003},
	author = {Le, X. C. and Cullen, W. R. and Reimer, K. J.}
}
@article {3091,
	title = {SPECIATION OF ARSENIC COMPOUNDS IN SOME MARINE ORGANISMS},
	journal = {Environmental Science \& Technology},
	volume = {28},
	number = {9},
	year = {1994},
	note = {ISI Document Delivery No.: PE258Times Cited: 43Cited Reference Count: 49},
	month = {Sep},
	pages = {1598-1604},
	type = {Article},
	abstract = {Speciation of arsenic compounds in some marine algae, bivalves, and crustaceans was studied by using two techniques: (i) high-performance liquid chromatography with inductively coupled plasma mass spectrometry detection and (ii) hydride generation atomic absorption spectrometry following microwave-assisted digestion. Arsenosugars were identified as the major arsenic compounds present in marine algae, whereas arsenobetaine was the dominant arsenic species present in crab and shrimp. In contrast to most previous reports, which claimed arsenobetaine as the only major arsenic species present in marine bivalves, this study revealed the presence of arsenosugars in addition to arsenobetaine in the bivalves. The speciation of arsenic in sample extracts and {\textquoteright}{\textquoteright}defrost liquid{\textquoteright}{\textquoteright} from previously frozen marine animal samples revealed that up to 48\% of the total arsenic in the sample can be released in the defrost liquid. Arsenic species found in the defrost liquid were identical with those in the sample extracts. Changes in arsenic speciation were observed in the sample extracts that were stored for a long term. Arsenobetaine in sample extracts that were stored at 4 degrees C for 9 months was decomposed to trimethylarsine oxide and two other unidentified arsenic species.},
	keywords = {ARSENIC COMPOUNDS, arsenobetaine, ATOMIC-ABSORPTION SPECTROMETRY, BOMBARDMENT MASS-SPECTROMETRY, ECKLONIA-RADIATA, HOMARUS-AMERICANUS, IDENTIFICATION, KELP, ORGANOARSENIC COMPOUNDS, TRACE-ELEMENTS, TRIMETHYLARSINE OXIDE},
	isbn = {0013-936X},
	url = {<Go to ISI>://A1994PE25800015},
	author = {Le, S. X. C. and Cullen, W. R. and Reimer, K. J.}
}
@article {2770,
	title = {BIOTRANSFORMATION OF [H-3] METHYLARSONIC ACID IN A STATIC SEAWATER SYSTEM CONTAINING MYTILUS-CALIFORNIANUS},
	journal = {Applied Organometallic Chemistry},
	volume = {7},
	number = {5},
	year = {1993},
	note = {ISI Document Delivery No.: LV681Times Cited: 8Cited Reference Count: 24},
	month = {Sep},
	pages = {329-334},
	type = {Article},
	abstract = {Mytius californianus exposed for 9 days to a seawater system containing [H-3]methylarsonic acid, was found to contain [H-3]methylarsonic acid along with [H-3]arsenobetaine and two unknown H-3-labeled compounds in the tissue parts of the mussel. A linear increase with time in the specific activity present in the flesh of Mytilus californianus was also observed. The highest specific activity was found in the visceral mass and the gills of the mussel.},
	keywords = {ALGAE, ARSENIC SPECIATION, arsenobetaine, ARSENOCHOLINE, BIOACCUMULATION, H-3 LABEL, IDENTIFICATION, marine environment, methylarsonic acid, METHYLATION, mussel, ORGANOARSENIC},
	isbn = {0268-2605},
	url = {<Go to ISI>://A1993LV68100005},
	author = {Cullen, W. R. and Pergantis, S. A.}
}
@article {2767,
	title = {DESORPTION CHEMICAL IONIZATION MASS-SPECTROMETRY OF ARSENIC COMPOUNDS PRESENT IN THE MARINE AND TERRESTRIAL ENVIRONMENT},
	journal = {Rapid Communications in Mass Spectrometry},
	volume = {7},
	number = {1},
	year = {1993},
	note = {ISI Document Delivery No.: KJ908Times Cited: 16Cited Reference Count: 18},
	month = {Jan},
	pages = {33-36},
	type = {Article},
	abstract = {The advantages of desorption chemical ionization mass spectrometry (DCI-MS) for characterizing arsenic compounds that exist in the environment include the presence in the spectra of recognizable molecular ions as well as structurally characteristic fragment ions. Satisfactory spectra can be obtained with 100 ng arsenic on the DCI filament, making the technique eminently suitable for the investigation of environmental samples.},
	keywords = {arsenobetaine, FAST ATOM BOMBARDMENT, IDENTIFICATION, SHRIMPS, TRIMETHYLARSINE OXIDE},
	isbn = {0951-4198},
	url = {<Go to ISI>://A1993KJ90800007},
	author = {Cullen, W. R. and Eigendorf, G. K. and Pergantis, S. A.}
}
@article {7295,
	title = {DECOMPOSITION OF ORGANOARSENIC COMPOUNDS BY USING A MICROWAVE-OVEN AND SUBSEQUENT DETERMINATION BY FLOW-INJECTION HYDRIDE GENERATION ATOMIC-ABSORPTION SPECTROMETRY},
	journal = {Applied Organometallic Chemistry},
	volume = {6},
	number = {2},
	year = {1992},
	note = {ISI Document Delivery No.: HQ168Times Cited: 61Cited Reference Count: 33INTERNATIONAL CONF ON ENVIRONMENTAL AND BIOLOGICAL ASPECTS OF MAIN-GROUP ORGANOMETALS ( ICEBAMO )SEP 15-19, 1991PADUA, ITALYUNIV PADUA, ITALIAN CHEM SOC},
	month = {Apr},
	pages = {161-171},
	type = {Proceedings Paper},
	abstract = {Environmentally important organoarsenicals such as arsenobetaine, arsenocholine and tetramethylarsonium ion do not form volatile hydrides under the commonly used analytical conditions on treatment with borohydride and it has been difficult to determine their concentrations without further derivatization. This paper describes a rapid method which completely decomposes and oxidizes these arsenicals to arsenate by using potassium persulphate and sodium hydroxide with the aid of microwave energy. The quantitative decomposition of these species permits their determination at low nanogram levels, by hydride generation atomic absorption spectrometry (HG AA). A new hydride generator which has high efficiency and minimum dead volume and therefore is suitable for flow injection analysis (FIA) is also described. A system combining flow injection analysis, on-line microwave oven digestion, and hydride generation followed by atomic absorption measurement, is developed. This system is capable of performing analysis at a sample throughput of 100-120 per hour. Calibration curves were linear from 10 to 200 ng cm-3 of arsenic and the detection limit was 5 ng cm-3 for a 100-mu-l injection or 0.5 ng of arsenic. All ten organoarsenic compounds studied gave arsenate as the decomposition product, which was confirmed by using molybdenum blue photometric measurement.},
	keywords = {ABSORPTION SPECTROMETRY, arsenic, arsenobetaine, atomic, DECOMPOSITION, DETERMINATION, DISSOLUTION, ENVIRONMENT, FLOW INJECTION ANALYSIS, HYDRIDE GENERATION, IDENTIFICATION, LIQUID-CHROMATOGRAPHY, MICROWAVE OVEN DIGESTION, MUSCLE REFERENCE MATERIAL, QUANTITATION, TRACE-ELEMENTS, WATER},
	isbn = {0268-2605},
	url = {<Go to ISI>://A1992HQ16800008},
	author = {Le, X. C. and Cullen, W. R. and Reimer, K. J.}
}
