@article {2476,
	title = {The ground state rotational spectrum of the fluorosulfate radical},
	journal = {Journal of Chemical Physics},
	volume = {130},
	number = {18},
	year = {2009},
	note = {ISI Document Delivery No.: 448LDTimes Cited: 2Cited Reference Count: 26Kolesnikova, Lucie Varga, Juraj Striteska, Lucie Nova Beckers, Helmut Willner, Helge Aubke, Friedhelm Urban, Stepan},
	month = {May},
	pages = {9},
	type = {Article},
	abstract = {The rotational spectra of the fluorosulfate (FSO3 center dot) molecular radical in its vibronic ground state were measured in the millimeter-wave region and analyzed in detail using the matrix elements of the rotational, fine, and hyperfine Hamiltonian terms. The analysis of the assigned transition frequencies made it possible to derive very precise values of the rotational, centrifugal distortion and fine structure constants and to confirm the C-3v molecular symmetry of the vibronic ground state unambiguously. In addition, an effective parameter of the "A(1)-A(2) splitting" was determined. The rotational transitions of the FSO3 center dot free radical were observed, identified, and analyzed for the first time.},
	keywords = {ASSIGNMENTS, BANDS, CLASSIFICATION, fluorine compounds, free radical reactions, ground states, HYPERFINE, LASER EXCITATION, lifetimes, millimetre wave spectra, molecular configurations, radiative, rotational states, STRUCTURE, SYMMETRIC-TOP MOLECULES, SYSTEM, vibronic states},
	isbn = {0021-9606},
	url = {<Go to ISI>://000266263200023},
	author = {Kolesnikova, L. and Varga, J. and Striteska, L. N. and Beckers, H. and Willner, H. and Aubke, F. and Urban, S.}
}
@article {558,
	title = {An NMR approach to structural proteomics},
	journal = {Proceedings of the National Academy of Sciences of the United States of America},
	volume = {99},
	number = {4},
	year = {2002},
	note = {ISI Document Delivery No.: 524UKTimes Cited: 109Cited Reference Count: 28},
	month = {Feb},
	pages = {1825-1830},
	type = {Article},
	abstract = {The influx of genomic sequence information has led to the concept of structural proteomics, the determination of protein structures on a genome-wide scale. Here we describe an approach to structural proteomics of small proteins using NMR spectroscopy. Over 500 small proteins from several organisms were cloned, expressed, purified, and evaluated by NMIR. Although there was variability among proteomes, overall 20\% of these proteins were found to be readily amenable to NMR structure determination. NMIR sample preparation was centralized in one facility, and a distributive approach was used for NMR data collection and analysis. Twelve structures are reported here as part of this approach, which allowed us to infer putative functions for several conserved hypothetical proteins.},
	keywords = {ASSIGNMENTS, CATH, DOMAIN, PROGRAM, PROTEINS, SPECTRA},
	isbn = {0027-8424},
	url = {<Go to ISI>://000174031100016},
	author = {Yee, A. and Chang, X. Q. and Pineda-Lucena, A. and Wu, B. and Semesi, A. and Le, B. and Ramelot, T. and Lee, G. M. and Bhattacharyya, S. and Gutierrez, P. and Denisov, A. and Lee, C. H. and Cort, J. R. and Kozlov, G. and Liao, J. and Finak, G. and Chen, L. and Wishart, D. and Lee, W. and McIntosh, L. P. and Gehring, K. and Kennedy, M. A. and Edwards, A. M. and Arrowsmith, C. H.}
}
@article {5098,
	title = {Dissecting the electrostatic interactions and pH-dependent activity of a family 11 glycosidase},
	journal = {Biochemistry},
	volume = {40},
	number = {34},
	year = {2001},
	note = {ISI Document Delivery No.: 466CYTimes Cited: 56Cited Reference Count: 50},
	month = {Aug},
	pages = {10115-10139},
	type = {Article},
	abstract = {Previous studies of the low molecular mass family 11 xylanase from Bacillus circulans show that the ionization state of the nucleophile (GIu78, pK(a) 4.6) and the acid/base catalyst (Glu 172, pK(a) 6.7) gives rise to its pH-dependent activity profile. Inspection of the crystal structure of BCX reveals that Glu78 and Glu172 are in very similar environments and are surrounded by several chemically equivalent and highly conserved active site residues. Hence, there are no obvious reasons why their apparent pKa values are different. To address this question, a mutagenic approach was implemented to determine what features establish the pKa values (measured directly by C-13 NMR and indirectly by pH-dependent activity profiles) of these two catalytic carboxylic acids. Analysis of several BCX variants indicates that the ionized form of Glu78 is preferentially stabilized over that of Glu 172 in part by stronger hydrogen bonds contributed by two well-ordered residues, namely, Tyr69 and Gln127. In addition, theoretical pKa calculations show that Glu78 has a lower pKa value than Glu 172 due to a smaller desolvation energy and more favorable background interactions with permanent partial charges and ionizable groups within the protein. The pKa value of Glu172 is in turn elevated due to electrostatic repulsion from the negatively charged glutamate at position 78. The results also indicate that all of the conserved active site residues act concertedly in establishing the pKa values of Glu78 and Glu 172, with no particular residue being singly more important than any of the others. In general, residues that contribute positive charges and hydrogen bonds serve to lower the pKa values of Glu78 and Glu172. The degree to which a hydrogen bond lowers a pKa value is largely dependent on the length of the hydrogen bond (shorter bonds lower pKa values more) and the chemical nature of the donor (COOH > OH > CONH2). In contrast, neighboring carboxyl groups can either lower or raise the pKa values of the catalytic glutamic acids depending upon the electrostatic linkage of the ionization constants of the residues involved in the interaction. While the pH optimum of BCX can be shifted from -1.1 to +0.6 pH units by mutating neighboring residues within the active site, activity is usually compromised due to the loss of important ground and/or transition state interactions. These results suggest that the pH optima of an enzyme might be best engineered by making strategic amino acid substitutions, at positions outside of the "core" active site, that electrostatically influence catalytic residues without perturbing their immediate structural environment.},
	keywords = {ASSIGNMENTS, BACILLUS-CIRCULANS XYLANASE, CATALYSIS, GLYCOSYL-ENZYME INTERMEDIATE, KINETIC-ANALYSIS, MASS-SPECTROMETRY, MECHANISMS, NMR, PK(A), PROTEIN, SITE NUCLEOPHILE, structures},
	isbn = {0006-2960},
	url = {<Go to ISI>://000170627800014},
	author = {Joshi, M. D. and Sidhu, G. and Nielsen, J. E. and Brayer, G. D. and Withers, S. G. and McIntosh, L. P.}
}
@article {4235,
	title = {Characterization of a buried neutral histidine in Bacillus circulans xylanase: Internal dynamics and interaction with a bound water molecule},
	journal = {Biochemistry},
	volume = {37},
	number = {7},
	year = {1998},
	note = {ISI Document Delivery No.: YZ886Times Cited: 13Cited Reference Count: 59},
	month = {Feb},
	pages = {1810-1818},
	type = {Article},
	abstract = {NMR spectroscopy was used to characterize the dynamic behavior of His149 in Bacillus circulans xylanase (BCX) and its interaction with an internal water molecule. Rate constants for the specific acid-and base-catalyzed exchange following bimolecular kinetics (EX2) of the nitrogen-bonded H-epsilon 2 of this buried, neutral histidine were determined, At pD(min) 7.0 and 30 degrees C, the lifetime for this proton is 9.9 h, corresponding to a protection factor of similar to 10(7) relative to that predicted for an exposed histidine, The apparent activation energies measured for specific acid and base catalysis (7.0 and 17.4 kcal/mol) indicate that exchange occurs via local structural fluctuations. Consistent with its buried environment, the N-epsilon 2-H bond vector of His149 shows restricted mobility, as evidenced by an order parameter S-2 = 0.83 determined from N-15 relaxation measurements, The crystal structure of BCX reveals that a conserved, buried water hydrogen-bonds to the H-epsilon 2 of His149. Strong support for this interaction in solution is provided by the observation of a negative nuclear Overhauser effect (NOE) and positive rotating-frame Overhauser effect (ROE) between His149 H-epsilon 2 and a water molecule with the same chemical shift as the bulk solvent. However, the chemical shift of H-epsilon 2 (12.2 ppm) and a D/H fractionation factor close to unity (0.89 +/- 0.02) indicate that this is nor a so-called low-barrier hydrogen bond. Lower and upper bounds on the lifetime of the internal water are estimated to be 10(-8) and 10(-3) s. Therefore the chemical exchange of solvent protons with those of His149 H-epsilon 2 and the diffusion or physical exchange of the internal water to which the histidine is hydrogen-bonded differ in rate by over 7 orders of magnitude.},
	keywords = {ACTIVE-SITE, AMIDE PROTON-EXCHANGE, ASSIGNMENTS, DOMAIN, HYDROGEN-BOND, NMR-SPECTROSCOPY, NUCLEAR MAGNETIC-RESONANCE, PROTEINS, relaxation, TRICHODERMA-REESEI},
	isbn = {0006-2960},
	url = {<Go to ISI>://000072304200010},
	author = {Connelly, G. P. and McIntosh, L. P.}
}
@article {3716,
	title = {NMR, MS and X-ray crystal structure determination of the bixin family of apocarotenoids},
	journal = {Journal of Chemical Research-S},
	number = {10},
	year = {1996},
	note = {ISI Document Delivery No.: VT903Times Cited: 4Cited Reference Count: 70},
	month = {Oct},
	pages = {446-\&},
	type = {Article},
	abstract = {The assignment of the H-1 and C-13 NMR spectra of alpha-bixin, methyl alpha-bixin, beta-bixin and methyl beta-bixin have been carried out using a combination of one- and two-dimensional techniques; the FAB(+) mass spectra of all these bixins had the molecular ion and methyl tropylium as high abundance peaks; also, the structures of alpha-bixin and methyl alpha-bixin have been confirmed by X-ray crystal structure determinations.},
	keywords = {ALL-TRANS, ANNATTO, ASSIGNMENTS, BETA-CAROTENE, COMPLETE H-1, FAST-ATOM-BOMBARDMENT, ORELLANA, SPECTRA, TANDEM MASS-SPECTROMETRY, THERMAL-DEGRADATION},
	isbn = {0308-2342},
	url = {<Go to ISI>://A1996VT90300006},
	author = {Kelly, D. R. and Edwards, A. A. and Parkinson, J. A. and Olovsson, G. and Trotter, J. and Jones, S. and Malik, K. M. A. and Hursthouse, M. B. and Hibbs, D. E.}
}
@article {3800,
	title = {Secondary structure and NMR assignments of Bacillus circulans xylanase},
	journal = {Protein Science},
	volume = {5},
	number = {6},
	year = {1996},
	note = {ISI Document Delivery No.: UP617Times Cited: 23Cited Reference Count: 74},
	month = {Jun},
	pages = {1118-1135},
	type = {Article},
	abstract = {Bacillus circulans xylanase (BCX) is a member of the family of low molecular weight endo-beta-(1,4)-xylanases. The main-chain H-1, C-13, and N-15 resonances of this 20.4-kDa enzyme were assigned using heteronuclear NMR experiments recorded on a combination of selectively and uniformly labeled protein samples. Using chemical shift, NOE, J coupling, and amide hydrogen exchange information, 14 beta-strands, arranged in a network of three beta-sheets, and a single cy-helix were identified in BCX. The NMR-derived secondary structure and beta-sheet topology agree closely with that observed in the crystal structure of this protein. The H-N of Ile 118 has a strongly upfield-shifted resonance at 4.03 ppm, indicative of a potential amide-aromatic hydrogen bond to the indole ring of Trp 71. This interaction, which is conserved in all low molecular weight xylanases of known structure, may play an important role in establishing the active site conformation of these enzymes. Following hen egg white and bacteriophage T4 lysozymes, B. circulans xylanase represents the third family of beta-glycanases for which extensive NMR assignments have been reported. These assignments provide the background for detailed studies of the mechanism of carbohydrate recognition and hydrolysis by this bacterial xylanase.},
	keywords = {amide-aromatic hydrogen bond, AMINO-ACID, ASSIGNMENTS, BACKBONE AMIDE, beta-glycanase, C-13-LABELED PROTEINS, C-ALPHA, chemical shift index, CHEMICAL-SHIFTS, COUPLING-CONSTANTS, LARGER PROTEINS, NMR, NUCLEAR-MAGNETIC-RESONANCE, SECONDARY STRUCTURE, SIDE-CHAIN RESONANCES, SOLVENT, SUPPRESSION, XYLANASE},
	isbn = {0961-8368},
	url = {<Go to ISI>://A1996UP61700014},
	author = {Plesniak, L. A. and Wakarchuk, W. W. and McIntosh, L. P.}
}
