@article {2072, title = {Phage display and crystallographic analysis reveals potential substrate/binding site interactions in the protein secretion chaperone CsaA from Agrobacterium tumefaciens}, journal = {Journal of Molecular Biology}, volume = {379}, number = {3}, year = {2008}, note = {ISI Document Delivery No.: 311FQTimes Cited: 0Cited Reference Count: 52Feldman, Anat R. Shapova, Yuliya A. Wu, Sampson S. T. Oliver, David C. Heller, Markus McIntosh, Lawrence P. Scott, Jamie K. Paetzel, Mark}, month = {Jun}, pages = {457-470}, type = {Article}, abstract = {The protein CsaA has been proposed to function as a protein secretion chaperone in bacteria that lack the Sec-dependent protein-targeting chaperone SecB. CsaA is a homodimer with two putative substrate-binding pockets, one in each monomer. To test the hypothesis that these cavities are indeed substrate-binding sites able to interact with other polypeptide chains, we selected a peptide that bound to CsaA from a random peptide library displayed on phage. Presented here is the structure of CsaA from Agrobacterium tumefaciens (AtCsaA) solved in the presence and absence of the selected peptide. To promote co-crystallization, the sequence for this peptide was genetically fused to the amino-terminus of AtCsaA. The resulting 1.65 angstrom resolution crystal structure reveals that the tethered peptide from one AtCsaA molecule binds to the proposed substrate-binding pocket of a symmetry-related molecule possibly mimicking the interaction between a pre-protein substrate and CsaA. The structure shows that the peptide lies in an extended conformation with alanine, proline and glutamine side chains pointing into the binding pocket. The peptide interacts with the atoms of the AtCsaA-binding pocket via seven direct hydrogen bonds. The side chain of a conserved pocket residue, Arg76, has an "up" conformation when the CsaA-binding site is empty and a "down" conformation when the CsaA-binding site is occupied, suggesting that this residue may function to stabilize the peptide in the binding cavity. The presented aggregation assays, phage-display analysis and structural analysis are consistent with AtCsaA being a general chaperone. The properties of the proposed CsaA-binding pocket/peptide interactions are compared to those from other structurally characterized molecular chaperones. (c) 2008 Elsevier Ltd. All rights reserved.}, keywords = {BACILLUS-SUBTILIS CSAA, BACTERIAL SIGNAL PEPTIDASE, BINDING PROTEIN, CHANNEL, CRYSTAL-STRUCTURE, CsaA, DISPLAY, LIBRARIES, molecular chaperone, phage, PROTEIN SECRETION, protein targeting, SECA, SEQUENCE, STRUCTURAL SUPERPOSITION, TRANSLOCATION}, isbn = {0022-2836}, url = {://000256586500006}, author = {Feldman, A. R. and Shapova, Y. A. and Wu, S. S. T. and Oliver, D. C. and Heller, M. and McIntosh, L. P. and Scott, J. K. and Paetzel, M.} } @article {2017, title = {Recombination of protein fragments: A promising approach toward engineering proteins with novel nanomechanical properties}, journal = {Protein Science}, volume = {17}, number = {10}, year = {2008}, note = {ISI Document Delivery No.: 351CKTimes Cited: 4Cited Reference Count: 50Balamurali, M. M. Sharma, Deepak Chang, Anderson Khor, Dingyue Chu, Ricky Li, Hongbin}, month = {Oct}, pages = {1815-1826}, type = {Article}, abstract = {Combining single molecule atomic force microscopy (AFM) and protein engineering techniques, here we demonstrate that we can use recombination-based techniques to engineer novel elastomeric proteins by recombining protein fragments from structurally homologous parent proteins. Using I27 and I32 domains from the muscle protein titin as parent template proteins, we systematically shuffled the secondary structural elements of the two parent proteins and engineered 13 hybrid daughter proteins. Although I27 and I32 are highly homologous, and homology modeling predicted that the hybrid daughter proteins fold into structures that are similar to that of parent protein, we found that only eight of the 13 daughter proteins showed beta-sheet dominated structures that are similar to parent proteins, and the other five recombined proteins showed signatures of the formation of significant alpha-helical or random coil-like structure. Single molecule AFM revealed that six recombined daughter proteins are mechanically stable and exhibit mechanical properties that are different from the parent proteins. In contrast, another four of the hybrid proteins were found to be mechanically labile and unfold at forces that are lower than the similar to 20 pN, as we could not detect any unfolding force peaks. The last three hybrid proteins showed interesting duality in their mechanical unfolding behaviors. These results demonstrate the great potential of using recombination-based approaches to engineer novel elastomeric protein domains of diverse mechanical properties. Moreover, our results also revealed the challenges and complexity of developing a recombination-based approach into a laboratory-based directed evolution approach to engineer novel elastomeric proteins.}, keywords = {ATOMIC-FORCE MICROSCOPY, BIOLOGICAL ROLES, COMPUTATIONAL DESIGN, ELASTICITY, elastomeric protein, EVOLUTION, IMMUNOGLOBULIN DOMAINS, MECHANICAL STABILITY, mechanical unfolding, MOLECULAR-DYNAMICS SIMULATION, recombination, SEQUENCE, SINGLE PROTEIN, single-molecule force spectroscopy, TITIN}, isbn = {0961-8368}, url = {://000259401900019}, author = {Balamurali, M. M. and Sharma, D. and Chang, A. and Khor, D. and Chu, R. and Li, H. B.} } @article {1163, title = {First passage times of driven DNA hairpin unzipping}, journal = {Physical Biology}, volume = {2}, number = {3}, year = {2005}, note = {ISI Document Delivery No.: 007TLTimes Cited: 11Cited Reference Count: 25}, month = {Sep}, pages = {166-174}, type = {Article}, abstract = {We model the dynamics of voltage-driven transport of DNA hairpins through transmembrane channels. A two-dimensional stochastic model of the DNA translocation process is fit to the measurements of Mathe, who pulled self-hybridized DNA hairpins through lipid-embedded alpha-hemolysin channels. As the channel was too narrow to accommodate hybridized DNA, dehybridization of the hairpin became the rate-limiting step of the transport process. We show that the mean first passage time versus voltage curve for the escape of the DNA from the transmembrane channel can be divided into two regions: (1) a low-voltage region where the DNA slides out of the pore in reverse and without undergoing significant dehybridization, and (2) a region where the DNA dehybridizes under the influence of the applied voltage and translocates across the membrane.}, keywords = {CHANNEL, DYNAMICS, FORCE, MEMBRANE, MOLECULES, NANOPORE, POLYMER TRANSLOCATION, PORE, SEQUENCE}, isbn = {1478-3967}, url = {://000234992600006}, author = {Lakatos, G. and Chou, T. and Bergersen, B. and Patey, G. N.} } @article {1291, title = {Plasticity of influenza haemagglutinin fusion peptides and their interaction with lipid bilayers}, journal = {Biophysical Journal}, volume = {88}, number = {1}, year = {2005}, note = {ISI Document Delivery No.: 884MYTimes Cited: 36Cited Reference Count: 72}, month = {Jan}, pages = {25-36}, type = {Article}, abstract = {A detailed molecular dynamics study of the haemagglutinin fusion peptide (N-terminal 20 residues of the HA2 subunits) in a model bilayer has yielded useful information about the molecular interactions leading to insertion into the lipids. Simulations were performed on the native sequence, as well as a number of mutant sequences, which are either fusogenic or nonfusogenic. For the native sequence and fusogenic mutants, the N-terminal 11 residues of the fusion peptides are helical and insert with a tilt angle of similar to30degrees with respect to the membrane normal, in very good agreement with experimental data. The tilted insertion of the native sequence peptide leads to membrane bilayer thinning and the calculated order parameters show larger disorder of the alkyl chains. These results indicate that the lipid packing is perturbed by the fusion peptide and could be used to explain membrane fusion. For the nonfusogenic sequences investigated, it was found that most of them equilibrate parallel to the interface plane and do not adopt a tilted conformation. The presence of a charged residue at the beginning of the sequence (G1E mutant) resulted in a more difficult case, and the outcomes do not fall straightforwardly into the general picture. Sequence searches have revealed similarities of the fusion peptide of influenza haemagglutinin with peptide sequences such as segments of porin, amyloid ab peptide, and a peptide from the prion sequence. These results confirm that the sequence can adopt different folds in different environments. The plasticity and the conformational dependence on the local environment could be used to better understand the function of fusion peptides.}, keywords = {ANALOGS, CONFORMATION, HEMAGGLUTININ, MEDIATED MEMBRANE-FUSION, MODEL MEMBRANES, MOLECULAR-DYNAMICS SIMULATION, MULTIPLE ALIGNMENT, RECEPTOR-BINDING, SEQUENCE, VIRAL FUSION, VIRUS}, isbn = {0006-3495}, url = {://000226090900006}, author = {Vaccaro, L. and Cross, K. J. and Kleinjung, J. and Straus, S. K. and Thomas, D. J. and Wharton, S. A. and Skehel, J. J. and Fraternali, F.} } @article {972, title = {Active site mutants of the "non-hydrolyzing" UDP-N-acetylglucosamine 2-epimerase from Escherichia coli}, journal = {Biochimica Et Biophysica Acta-Proteins and Proteomics}, volume = {1700}, number = {1}, year = {2004}, note = {ISI Document Delivery No.: 833VCTimes Cited: 4Cited Reference Count: 26}, month = {Jul}, pages = {85-91}, type = {Article}, abstract = {The "non-hydrolyzing" bacterial UDP-N-acetylglucosamine 2-epimerase catalyzes the reversible interconversion of UDP-N-acetylglucosarnine (UDP-GlcNAc) and UDP-N-acetylmannosamine (UDP-ManNAc). This homodimeric enzyme is allosterically activated by its substrate, UDP-GlcNAc, and it is thought that one subunit plays a regulatory role, while that of the other plays a catalytic role. In this work, five active site mutants were prepared (D95N, E117Q, E131Q, K15A, and H213N) and analyzed in terms of their effects on binding, catalysis, and allosteric regulation. His213 appears to play a role in UDP binding and may also assist in catalysis and/or regulation, but is not a key catalytic residue. Lys15 appears to be quite important for binding. All three of the carboxylate mutants showed dramatic decreases in the value of k(cat) but relatively unaffected values of Km. Thus, these residues are playing key roles in catalysis and/or regulation. In the case of E117Q, the reaction intermediates are released into solution at a rate comparable to that of the overall catalysis. This may indicate that Glu117 plays the role as an acid/base catalyst in the second step of the UDP-GlcNAc epimerization reaction. All three carboxylate mutants were found to exhibit impaired allosteric control. (C) 2004 Elsevier B.V. All rights reserved.}, keywords = {2-acetamidoglucal, 2-EPIMERASE/N-ACETYLMANNOSAMINE KINASE, ACID BIOSYNTHESIS, allosteric regulation, enterobacterial common antigen, EPIMERIZATION, HOMOLOGY, MECHANISM, MUTAGENESIS, RAT-LIVER, SEQUENCE, sialic acid, STREPTOCOCCUS-PNEUMONIAE, TRANSFERASES, UDP-N-acetylmannosamine}, isbn = {1570-9639}, url = {://000222367400011}, author = {Samuel, J. and Tanner, M. E.} } @article {1023, title = {The NeuC protein of Escherichia coli K1 is a UDP N-acetylglucosamine 2-epimerase}, journal = {Journal of Bacteriology}, volume = {186}, number = {3}, year = {2004}, note = {ISI Document Delivery No.: 766HUTimes Cited: 18Cited Reference Count: 43}, month = {Feb}, pages = {706-712}, type = {Article}, abstract = {The K1 capsule is an essential virulence determinant of Escherichia coli strains that cause meningitis in neonates. Biosynthesis and transport of the capsule, an alpha-2,8-linked polymer of sialic acid, are encoded by the 17-kb kps gene cluster. We deleted neuC, a K1 gene implicated in sialic acid synthesis, from the chromosome of EV36, a K-12-K1 hybrid, by allelic exchange. Exogenously added sialic acid restored capsule expression to the deletion strain (DeltaneuC), confirming that NeuC is necessary for sialic acid synthesis. The deduced amino acid sequence of NeuC showed similarities to those of UDP-N-acetylglucosamine (GlcNAc) 2-epimerases from both prokaryotes and eukaryotes. The NeuC homologue from serotype III Streptococcus agalactiae complements DeltaneuC. We cloned the neuC gene into an intein expression vector to facilitate purification. We demonstrated by paper chromatography that the purified neuC gene product catalyzed the formation of [2-C-14]acetamidoglucal and [N-C-14]acetylmannosamine (ManNAc) from UDP-[C-14]GlcNAc. The formation of reaction intermediate 2-acetamidoglucal with the concomitant release of UDP was confirmed by proton and phosphorus nuclear magnetic resonance spectroscopy. NeuC could not use GlcNAc as a substrate. These data suggest that neuC encodes an epimerase that catalyzes the formation of ManNAc from UDP-GlcNAc via a 2-acetamidoglucal intermediate. The unexpected release of the glucal intermediate and the extremely low rate of ManNAc formation likely were a result of the in vitro assay conditions, in which a key regulatory molecule or protein was absent.}, keywords = {2-EPIMERASE/N-ACETYLMANNOSAMINE KINASE, ACETYLNEURAMINIC ACID SYNTHETASE, EXPRESSION, GENE-PRODUCT, NEISSERIA-MENINGITIDIS, POLYSACCHARIDE BIOSYNTHESIS, POLYSIALIC ACID, RAT-LIVER, SEQUENCE, SIALIC-ACID}, isbn = {0021-9193}, url = {://000188371600014}, author = {Vann, W. F. and Daines, D. A. and Murkin, A. S. and Tanner, M. E. and Chaffin, D. O. and Rubens, C. E. and Vionnet, J. and Silver, R. P.} } @article {449, title = {Collision cross sections of gas phase DNA ions}, journal = {International Journal of Mass Spectrometry}, volume = {219}, number = {1}, year = {2002}, note = {ISI Document Delivery No.: 591BVTimes Cited: 4Cited Reference Count: 27}, month = {Aug}, pages = {161-170}, type = {Article}, abstract = {Collision cross sections of negative ions of a 28-, 40- and 55-mer of single stranded DNA have been measured by an energy loss method, and compared to collision cross sections of proteins of nearly the same molecular weight-ubiquitin, cytochrome c and apomyoglobin, respectively. The oligonucleotides produce negative charge states in electrospray ionization (ESI) similar to the positive charge states produced by the proteins denatured in solution. Cross sections for deoxynucleotide ions increase with charge state in a manner similar to those of protein ions. However, for a given molecular weight and charge state, the cross sections of the oligodeoxynucleotide ions are about 22\% lower than those of the proteins. (C) 2002 Elsevier Science B.V. All rights reserved.}, keywords = {collision cross sections, CONFORMATION, CONFORMERS, DNA ions, ELECTROSPRAY MASS-SPECTROMETRY, gas phase, MYOGLOBIN, PROTEIN IONS, SEQUENCE, VACUUM}, isbn = {1387-3806}, url = {://000177860600015}, author = {Moradian, A. and Scalf, M. and Westphall, M. S. and Smith, L. M. and Douglas, D. J.} } @article {5138, title = {The structure of L-ribulose-5-phosphate 4-epimerase: An aldolase-like platform for epimerization}, journal = {Biochemistry}, volume = {40}, number = {49}, year = {2001}, note = {ISI Document Delivery No.: 500CJTimes Cited: 18Cited Reference Count: 45}, month = {Dec}, pages = {14763-14771}, type = {Article}, abstract = {The structure of L-ribulose-5 -phosphate 4-epimerase from E. coli has been solved to 2.4 Angstrom resolution using X-ray diffraction data. The structure is homo-tetrameric and displays C-4 symmetry. Each subunit has a single domain comprised of a central beta -sheet flanked on either side by layers of alpha -helices. The active site is identified by the position of the catalytic zinc residue and is located at the interface between two adjacent subunits. A remarkable feature of the structure is that it shows a very close resemblance to that of L-fuculose-1-phosphate aldolase. This is consistent with the notion that both enzymes belong to a superfamily of epimerases/aldolases that catalyze carbon-carbon bond cleavage reactions via a metal-stabilized enolate intermediate. Detailed inspection of the epimerase structure, however, indicates that despite the close overall structural similarity to class II aldolases, the enzyme has evolved distinct active site features that promote its particular chemistry.}, keywords = {CHEMISTRY, CLASS-II, CLEAVAGE, ENZYME, ESCHERICHIA-COLI, EVOLUTION, GALACTOSE, L-FUCULOSE-1-PHOSPHATE ALDOLASE, MECHANISM, SEQUENCE, SUPERFAMILIES}, isbn = {0006-2960}, url = {://000172608100005}, author = {Luo, Y. and Samuel, J. and Mosimann, S. C. and Lee, J. E. and Tanner, M. E. and Strynadka, N. C. J.} } @article {4873, title = {Zinc-bundle structure of the essential RNA polymerase subunit RPB10 from Methanobacterium thermoautotrophicum}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {97}, number = {12}, year = {2000}, note = {ISI Document Delivery No.: 322UATimes Cited: 14Cited Reference Count: 34}, month = {Jun}, pages = {6316-6321}, type = {Article}, abstract = {The RNA polymerase subunit RPB10 displays a high level of conservation across archaea and eukarya and is required for cell viability in yeast, Structure determination of this RNA polymerase subunit from Methanobacterium thermoautotrophicum reveals a topology, which we term a zinc-bundle, consisting of three cu-helices stabilized by a zinc ion. The metal ion is bound within an atypical CX2CXnCC sequence motif and serves to bridge an N-terminal loop with helix 3, This represents an example of two adjacent zinc-binding Cys residues within an alpha-helix conformation. Conserved surface features of RPB10 include discrete regions of neutral, acidic, and basic residues, the latter being located around the zinc-binding site. One or more of these regions may contribute to the role of this subunit as a scaffold protein within the polymerase holoenzyme.}, keywords = {ABC10-BETA, ARCHAEA, COMMON SUBUNITS, DOMAIN, genomics, IN-VITRO, PROTEINS, RESOLUTION, SEQUENCE, transcription}, isbn = {0027-8424}, url = {://000087526300018}, author = {Mackereth, C. D. and Arrowsmith, C. H. and Edwards, A. M. and McIntosh, L. P.} } @article {4298, title = {Epimerization via carbon-carbon bond cleavage. L-ribulose-5-phosphate 4-epimerase as a masked class II aldolase}, journal = {Biochemistry}, volume = {37}, number = {16}, year = {1998}, note = {ISI Document Delivery No.: ZM208Times Cited: 32Cited Reference Count: 35}, month = {Apr}, pages = {5746-5754}, type = {Article}, abstract = {Studies indicating that the E. coli L-ribulose-5-phosphate 4-epimerase employs an "aldolase-like" mechanism are reported. This NAD(+)-independent enzyme epimerizes a steseocenter that does not bear an acidic proton and therefore it cannot utilize a simple deprotonation-reprotonation mechanism. Sequence similarities between the epimerase and the class II L-fuculose-1-phosphate aldolase suggest that the two may be evolutionarily related and that the epimerization may occur via carbon-carbon bond cleavage and re-formation. Conserved residues thought to provide the metal ion ligands of the epimerase have been modified using site-directed mutagenesis. The resulting mutants show low k(cat) values in addition to a reduced affinity for Zn2+. These observations serve to establish that there is a structural link between between the active site geometry of the epimerase and the aldolase. In addition, the H97N mutant was found to catalyze the condensation of dihydroxyacetone and glycolaldehyde phosphate to produce a mixture of L-ribulose-5-phosphate and D-xylulose-5-phosphate. This observation of aldolase activity establishes that the epimerase active site is capable of promoting carbon-carbon bond cleavage. Furthermore, glycolaldehyde phosphate was shown to be a competitive inhibitor of the mutant enzyme (K-t = 0.37 mM) but not of the wild-type enzyme. The mutation apparently causes the epimerase to become "leaky" and enables it to bind/generate the normal reaction intermediates from the unbound aldol cleavage products.}, keywords = {ENZYMES, ESCHERICHIA-COLI, L-FUCULOSE-1-PHOSPHATE ALDOLASE, MECHANISM, MUTAGENESIS, ORGANIC-SYNTHESIS, PCR, PURIFICATION, SEQUENCE, SITE}, isbn = {0006-2960}, url = {://000073515500048}, author = {Johnson, A. E. and Tanner, M. E.} } @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 = {://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 {3805, title = {Enzymatic formation and release of a stable glycal intermediate: The mechanism of the reaction catalyzed by UDP-N-acetylglucosamine 2-epimerase}, journal = {Journal of the American Chemical Society}, volume = {118}, number = {12}, year = {1996}, note = {ISI Document Delivery No.: UC380Times Cited: 19Cited Reference Count: 25}, month = {Mar}, pages = {3033-3034}, type = {Article}, keywords = {ACID, BACTERIOPHAGE-N4 ADSORPTION, biosynthesis, enterobacterial common antigen, ESCHERICHIA-COLI, MUTANTS, POSITIONAL ISOTOPE EXCHANGE, SEQUENCE}, isbn = {0002-7863}, url = {://A1996UC38000035}, author = {Sala, R. F. and Morgan, P. M. and Tanner, M. E.} } @article {3708, title = {Interaction of soluble cellooligosaccharides with the N-terminal cellulose-binding domain of Cellulomonas fimi CenC .2. NMR and ultraviolet absorption spectroscopy}, journal = {Biochemistry}, volume = {35}, number = {44}, year = {1996}, note = {ISI Document Delivery No.: VR098Times Cited: 68Cited Reference Count: 46}, month = {Nov}, pages = {13895-13906}, type = {Article}, abstract = {The N-terminal cellulose-binding domain (CBDN1) from Cellulomonas fimi beta-1,4-glucanase CenC binds amorphous but not crystalline cellulose. To investigate the structural and thermodynamic bases of cellulose binding, NMR and difference ultraviolet absorbance spectroscopy were used in parallel with calorimetry (Tomme, P., Creagh, A. L., Kilburn, D. G., \& Haynes, C. A., (1996) Biochemistry 35, 13885-13894] to characterize the interaction of soluble cellooligosaccharides with CBDN1 Association constants, determined from the dependence of the amide H-1 and N-15 chemical shifts of CBDN1 upon added sugar, increase from 180 +/- 60 M(-1) for cellotriose to 4 200 +/- 720 M(-1) for cellotetraose, 34 000 +/- 7 600 M(-1) for cellopentaose, and an estimate of 50 000 M(-1) for cellohexaose. This implies that the CBDN1 cellulose-binding site spans approximately five glucosyl units, On the basis of the observed patterns of amide chemical shift changes, the cellooligosaccharides bind along a five-stranded beta-sheet that forms a concave face of the jelly-roll beta-sandwich structure of CBDN1. This beta-sheet contains a strip of hydrophobic side chains flanked on both sides by polar residues, NMR and difference ultraviolet absorbance measurements also demonstrate that tyrosine, but not tryptophan, side chains may be involved in oligosaccharide binding. These results lead to a model in which CBDN1 interacts with soluble cellooligosaccharides and, by inference, with single polysaccharide chains in regions of amorphous cellulose, primarily through hydrogen bonding to the equatorial hydroxyl groups of the pyranose rings. Van der against the apolar side chains may augment binding. CBDN1 stands in marked contrast to previously characterized CBDs that absorb to crystalline cellulose via a flat binding surface dominated by exposed aromatic rings.}, keywords = {BACKBONE H-1, CHEMICAL-SHIFTS, ESCHERICHIA-COLI, EXPRESSION, HIGH-LEVEL, NUCLEAR-MAGNETIC-RESONANCE, PROTEIN, REESEI CELLOBIOHYDROLASE-I, SEQUENCE, TRICHODERMA-REESEI, TRYPTOPHAN RESIDUES}, isbn = {0006-2960}, url = {://A1996VR09800005}, author = {Johnson, P. E. and Tomme, P. and Joshi, M. D. and McIntosh, L. P.} } @article {3478, title = {MODULATION OF TRANSCRIPTION FACTOR ETS-1 DNA-BINDING - DNA-INDUCED UNFOLDING OF AN ALPHA-HELIX}, journal = {Science}, volume = {269}, number = {5232}, year = {1995}, note = {ISI Document Delivery No.: RX194Times Cited: 143Cited Reference Count: 49}, month = {Sep}, pages = {1866-1869}, type = {Article}, abstract = {Conformational changes, including local protein folding, play important roles in protein-DNA interactions. Here, studies of the transcription factor Ets-1 provided evidence that local protein unfolding also can accompany DNA binding. Circular dichroism and partial proteolysis showed that the secondary structure of the Ets-1 DNA-binding domain is unchanged in the presence of DNA. In contrast, DNA allosterically induced the unfolding of an cr helix that lies within a flanking region involved in the negative regulation of DNA binding. These findings suggest a structural basis for the intramolecular inhibition of DNA binding and a mechanism for the cooperative partnerships that are common features of many eukaryotic transcription factors.}, keywords = {BASIC REGION, CRYSTAL-STRUCTURE, DOMAIN, FAMILY, GCN4, INDUCED CONFORMATIONAL CHANGE, PROTEIN-KINASES, REPRESSOR, SEQUENCE, SUBUNITS}, isbn = {0036-8075}, url = {://A1995RX19400036}, author = {Petersen, J. M. and Skalicky, J. J. and Donaldson, L. W. and McIntosh, L. P. and Alber, T. and Graves, B. J.} } @article {3013, title = {THE CELLULOSE-BINDING DOMAIN OF ENDOGLUCANASE-A (CENA) FROM CELLULOMONAS-FIMI - EVIDENCE FOR THE INVOLVEMENT OF TRYPTOPHAN RESIDUES IN BINDING}, journal = {Molecular Microbiology}, volume = {11}, number = {4}, year = {1994}, note = {ISI Document Delivery No.: MW536Times Cited: 96Cited Reference Count: 46}, month = {Feb}, pages = {747-755}, type = {Article}, abstract = {Cellulomonas fimi endo-beta-1-4-glucanase A (CenA) contains a discrete N-terminal cellulose-binding domain (CBDCenA). Related CBDs occur in at least 16 bacterial glycanases and are characterized by four highly conserved Trp residues, two of which correspond to W14 and W68 of CBDCenA. The adsorption of CBDCenA to crystalline cellulose was compared with that of two Trp mutants (W14A and W68A). The affinities of the mutant CBDs for cellulose were reduced by approximately 50- and 30-fold, respectively, relative to the wild type. Physical measurements indicated that the mutant CBDs fold normally. Fluorescence data indicated that W14 and W68 were exposed on the CBD, consistent with their participation in binding to cellobiosyl residues on the cellulose surface.}, keywords = {BACTERIAL CELLULASE, CELLOBIOHYDROLASES, CLONING, DNA, FLUORESCENS SUBSP CELLULOSA, FUNCTIONAL DOMAINS, GENE, PROTEIN, SEQUENCE, THERMOMONOSPORA-FUSCA}, isbn = {0950-382X}, url = {://A1994MW53600013}, author = {Din, N. and Forsythe, I. J. and Burtnick, L. D. and Gilkes, N. R. and Miller, R. C. and Warren, R. A. J. and Kilburn, D. G.} } @article {3144, title = {TECHNOLOGY FOR REGENERABLE BIOSENSOR PROBES BASED ON ENZYME CELLULOSE-BINDING DOMAIN CONJUGATES}, journal = {Biotechnology Progress}, volume = {10}, number = {4}, year = {1994}, note = {ISI Document Delivery No.: PC847Times Cited: 9Cited Reference Count: 39}, month = {Jul-Aug}, pages = {433-440}, type = {Article}, abstract = {The application of enzyme-based biosensors for on-line bioprocess monitoring and control has been slowed by problems relating to the in situ sterilizability of the probe and the stability of the enzyme component. A novel technology with the potential to address both of these difficulties is presented here, The approach is based on the reversible immobilization of enzymes conjugated with the cellulose binding domain (CBD) of cellulases from Cellulomonas fimi. A regenerable biosensor electrode can be configured with a cellulose matrix onto which the enzyme-CBD conjugate can be repeatedly loaded (bound by the CBD) and subsequently eluted by perfusing the cellulose matrix with the appropriate solution. Glucose oxidase (GOx) conjugated to CBD with glutaraldehyde was used in an experimental glucose biosensor to demonstrate the feasibility of multiple cycles of loading and elution of the conjugate. Michaelis-Menten enzyme kinetics provided an empirical model for the calibration of the experimental biosensor. The development of a computer-controlled prototype glucose biosensor and a fermentation monitoring system based on this approach is discussed.}, keywords = {CLONING, electrode, ESCHERICHIA-COLI, EXOGLUCANASE, FIMI, GENE, GLUCOSE-OXIDASE, IMMOBILIZATION, ONLINE DETERMINATION, SEQUENCE}, isbn = {8756-7938}, url = {://A1994PC84700014}, author = {Phelps, M. R. and Hobbs, J. B. and Kilburn, D. G. and Turner, R. F. B.} } @article {6841, title = {LASER DESORPTION IONIZATION FOURIER-TRANSFORM ION-CYCLOTRON RESONANCE MASS-SPECTROMETRY OF CARBOHYDRATES .1. BACTERIAL OLIGOSACCHARIDES CONTAINING NEURAMINIC ACID OR PYRUVIC-ACID ACETAL GROUPS}, journal = {Analytica Chimica Acta}, volume = {241}, number = {2}, year = {1990}, note = {ISI Document Delivery No.: EU533Times Cited: 14Cited Reference Count: 342ND INTERNATIONAL SYMP ON APPLIED MASS SPECTROMETRY IN THE HEALTH SCIENCESAPR 17-20, 1990BARCELONA, SPAINASTRA, APPL BIOSYST, BOEHRINGER MANNHEIM, COMISSIO INTERDEPT RECERCA \& INNOVAC TECHNOL, CONSEJO SUPER INVESTIGAC CIEN, CONSELLERIA ENSENYAMENT GENERALITAT CATALUNYA, FINNIGAN MAT, FONDO INVESTIGAC SANITARIA, REAL SOC ESPANOLA QUIMICA, GRP CROMATOG \& TECN AFINES, HEWLETT PACKARD}, month = {Dec}, pages = {187-199}, type = {Proceedings Paper}, abstract = {The positive- and negative-ion laser desorption ionization Fourier transform ion cyclotron resonance mass spectra of two known, underivatized, linear oligosaccharides obtained by enzymatic hydrolysis with bacterial viruses of the corresponding native bacterial capsular polysaccharides were analyzed. The high-resolution spectra, estimated to be from less than 1 nmol of sample, showed prominent pseudo-molecular ions, as well as fragment ions derived from glycosidic bond and ring cleavages. For some of these frequently observed ring fragments, structures are proposed by analogy to known even-electron gas phase fragmentations and even-electron solution chemistry. The structures of the capsular biopolymers were delineated from these fragmentations, confirming that Klebsiella pneumoniae serotype K3 capsular polysaccharide is made up of a pentasaccharide repeating unit, consisting of four hexoses, one hexuronic acid and one pyruvic acid acetal; and confirming that the tetrasaccharide repeating unit of Escherichia coli serotype K9 is composed of two hexoses, one acetamido hexose and one N-acetyl neuraminic acid. The analysis of oligosaccharides containing N-acetylated sugars was complicated by the fact that an amino hexose attached to a -C2H3O2 ring fragment shares the same elemental formula as an acetamido hexose. Nevertheless, other less ambiguous structural ions could be used for sequencing. Furthermore, analysis of the ring fragments also provided some indication of the positions of linkage of certain monosaccharide residues.}, keywords = {BACTERIOPHAGE-BORNE ENZYMES, CAPSULAR, FAB, FAST ATOM BOMBARDMENT, GLYCOSIDES, ION CYCLOTRON RESONANCE, LASER DESORPTION IONIZATION, MS, OLIGOSACCHARIDES, POLYSACCHARIDE, SEQUENCE, SPECTRA}, isbn = {0003-2670}, url = {://A1990EU53300004}, author = {Lam, Z. and Comisarow, M. B. and Dutton, G. G. S. and Parolis, H. and Parolis, L. A. S. and Bjarnason, A. and Weil, D. A.} }