@article {1436,
	title = {Glycosynthase-based synthesis of xylo-oligosaccharides using an engineered retaining xylanase from Cellulomonas fimi},
	journal = {Organic \& Biomolecular Chemistry},
	volume = {4},
	number = {10},
	year = {2006},
	note = {ISI Document Delivery No.: 041NHTimes Cited: 20Cited Reference Count: 39},
	pages = {2025-2032},
	type = {Article},
	abstract = {Glycosynthases are synthetic enzymes derived from retaining glycosidases in which the catalytic nucleophile has been replaced. The mutation allows irreversible glycosylation of sugar acceptors using glycosyl fluoride donors to afford oligosaccharides without any enzymatic hydrolysis. Glycosynthase technology has proven fruitful for the facile synthesis of useful oligosaccharides, therefore the expansion of the glycosynthase repertoire is of the utmost importance. Herein, we describe for the first time a glycosynthase, derived from a retaining xylanase, that synthesizes a range of xylo-oligosaccharides. The catalytic domain of the retaining endo-1,4-beta-xylanase from Cellulomonas fimi (CFXcd) was successfully converted to the corresponding glycosynthase by mutation of the catalytic nucleophile to a glycine residue. The mutant enzyme (CFXcd-E235G) was found to catalyze the transfer of a xylobiosyl moiety from alpha-xylobiosyl fluoride to either p-nitrophenyl beta-xylobioside or benzylthio beta-xylobioside to afford oligosaccharides ranging in length from tetra- to dodecasaccharides. These products were purified by high performance liquid chromatography in greater than 60\% combined yield. H-1 and C-13 NMR spectroscopic analyses of the isolated p-nitrophenyl xylotetraoside and p-nitrophenyl xylohexaoside revealed that CFXcd-E235G catalyzes both the regio- and stereo-selective synthesis of xylo-oligosaccharides containing, exclusively, beta-(1 {\textendash}> 4) linkages.},
	keywords = {4-GLYCANASE, BETA-1, DIRECTED EVOLUTION, EFFICIENT SYNTHESIS, ENZYMATIC-SYNTHESIS, GLYCOSIDASES, MASS-SPECTROMETRY, SPECIFICITY, SUBSTRATE, TRANSGLYCOSYLATION, XYLOOLIGOSACCHARIDES},
	isbn = {1477-0520},
	url = {<Go to ISI>://000237462400022},
	author = {Kim, Y. W. and Fox, D. T. and Hekmat, O. and Kantner, T. and McIntosh, L. P. and Warren, R. A. J. and Withers, S. G.}
}
@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 {444,
	title = {Carbohydrate-binding modules recognize fine substructures of cellulose},
	journal = {Journal of Biological Chemistry},
	volume = {277},
	number = {52},
	year = {2002},
	note = {ISI Document Delivery No.: 631QDTimes Cited: 20Cited Reference Count: 36},
	month = {Dec},
	pages = {50245-50254},
	type = {Article},
	abstract = {Competition isotherms are used to identify the set of cellulose substructures to which cellulose binding modules (CBMs) from families 2a, 3, 4, 9, and 17 bind. The experiments are based on coupling a unique fluorescent tag to each CBM in a manner that does not alter the natural binding properties of the CBM and therefore allows the surface and solution concentrations of each CBM to be monitored as a function of time and composition. Adsorption and surface exchange of like or competing CBMs are monitored using a range of cellulose preparations varying in both crystallinity and provenance. CBMs from families 2a, 3,4,9, and 17 are shown to recognize different physical forms of prepared cellulose. The demonstration of the very fine binding specificity of cellulose-specific CBMs implies that the polysaccharide targets of CBMs extend down to the resolution of cellulose microstructures.},
	keywords = {BACTERIAL, CELLULASE, CRYSTALLINE CELLULOSE, DOMAIN, EXOGLUCANASE, FIMI CENC, NMR-SPECTROSCOPY, PROTEIN-A, SPECIFICITY, TRYPTOPHAN RESIDUES, XYLANASE 10A},
	isbn = {0021-9258},
	url = {<Go to ISI>://000180177700007},
	author = {McLean, B. W. and Boraston, A. B. and Brouwer, D. and Sanaie, N. and Fyfe, C. A. and Warren, R. A. J. and Kilburn, D. G. and Haynes, C. A.}
}
@article {4578,
	title = {The cellulose-binding domains from Cellulomonas fimi beta-1,4-glucanase CenC bind nitroxide spin-labeled cellooligosaccharides in multiple orientations},
	journal = {Journal of Molecular Biology},
	volume = {287},
	number = {3},
	year = {1999},
	note = {ISI Document Delivery No.: 184RGTimes Cited: 38Cited Reference Count: 46},
	month = {Apr},
	pages = {609-625},
	type = {Article},
	abstract = {The N-terminal cellulose-binding domains CBDN1 and CBDN2 from Cellulomonas fimi cellulase CenC each adopt a jelly-roll beta-sandwich structure with a cleft into which amorphous cellulose and soluble cellooligosaccharides bind. To determine the orientation of the sugar chain within these binding clefts, the association of TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl-4-yl) spin-labeled derivatives of cellotriose and cellotetraose with isolated CBDN1 and CBDN2 was studied using heteronuclear H-1-N-15 NMR spectroscopy. Quantitative binding measurements indicate that the TEMPO moiety does not significantly perturb the affinity of the cellooligo-saccharide derivatives for the CBDs. The paramagnetic enhancements of the amide H-1(N) longitudinal (Delta R-1) and transverse (Delta R-2) relaxation rates were measured by comparing the effects of TEMPO-cellotetraose in its nitroxide (oxidized) and hydroxylamine (reduced) forms on the two CBDs. The bound spin-label affects most significantly the relaxation rates of amides located at both ends of the sugar-binding cleft of each CBD. Similar results are observed with TEMPO-cellotriose bound to CBDN1. This demonstrates that the TEMPO-labeled cellooligosaccharides, and by inference strands of amorphous cellulose, can associate with CBDN1 and CBDN2 in either orientation across their beta-sheet binding clefts. The ratio of the association constants for binding in each of these two orientations is estimated to be within a factor of five to tenfold. This finding is consistent with the approximate symmetry of the hydrogen-bonding groups on both the cellooligosaccharides and the residues forming the binding clefts of the CenC CBDs. (C) 1999 Academic Press.},
	keywords = {CELLULASES, ENDOGLUCANASE, GLYCOSYNTHASE, MAGNETIC-RESONANCE SPECTROSCOPY, NMR, protein-carbohydrate interaction, PROTEINS, SENSITIVITY, SITE, SPECIFICITY, spin label},
	isbn = {0022-2836},
	url = {<Go to ISI>://000079626300013},
	author = {Johnson, P. E. and Brun, E. and Mackenzie, L. F. and Withers, S. G. and McIntosh, L. P.}
}
@article {4647,
	title = {The structures of the neurotrophin 4 homodimer and the brain-derived neurotrophic factor/neurotrophin 4 heterodimer reveal a common Trk-binding site},
	journal = {Protein Science},
	volume = {8},
	number = {12},
	year = {1999},
	note = {ISI Document Delivery No.: 266RPTimes Cited: 24Cited Reference Count: 45},
	month = {Dec},
	pages = {2589-2597},
	type = {Article},
	abstract = {The neurotrophins are growth factors that are involved in the development and survival of neurons. Neurotrophin release by a target tissue results in neuron growth along the neurotrophin concentration gradient, culminating in the eventual innervation of the target tissue. These activities are mediated through trk cell surface receptors. We have determined the structures of the heterodimer formed between brain-derived neurotrophic factor (BDNF) and neurotrophin 4 (NT4), as well as the structure of homodimer of NT4. We also present the structure of the Neurotrophin 3 homodimer, which is refined to higher resolution than previously published. These structures provide the first views of the architecture of the NT4 protomer. Comparison of the surface of a model of the BDNF homodimer with the structures of the neurotrophin homodimers reveals common features that may be important in the binding between the neurotrophins and their receptors. In particular, there exists an analogous region on the surface of each neurotrophin that is likely to be involved in trk receptor binding. Variations in sequence on the periphery of this common region serve to confer trk receptor specificity.},
	keywords = {BDNF, CELLS, CRYSTAL-STRUCTURE, CRYSTALLOGRAPHY, DIFFERENTIATION, nerve growth factor, NERVE GROWTH-FACTOR, NGF, PURIFICATION, RECEPTOR, RECEPTORS, RECOGNITION, SPECIFICITY},
	isbn = {0961-8368},
	url = {<Go to ISI>://000084314100005},
	author = {Robinson, R. C. and Radziejewski, C. and Spraggon, G. and Greenwald, J. and Kostura, M. R. and Burtnick, L. D. and Stuart, D. I. and Choe, S. and Jones, E. Y.}
}
@article {7321,
	title = {BINDING-ENERGY AND CATALYSIS - FLUORINATED AND DEOXYGENATED GLYCOSIDES AS MECHANISTIC PROBES OF ESCHERICHIA-COLI (LACZ) BETA-GALACTOSIDASE},
	journal = {Biochemical Journal},
	volume = {286},
	year = {1992},
	note = {ISI Document Delivery No.: JN815Times Cited: 86Cited Reference Count: 40Part 3},
	month = {Sep},
	pages = {721-727},
	type = {Article},
	abstract = {Kinetic parameters for the hydrolysis of a series of deoxy and deoxyfluoro analogues of 2{\textquoteright},4{\textquoteright}-dinitrophenyl beta-D-galactopyranoside by Escherichia coli (lacZ) beta-galactosidase have been determined and rates found to be two to nine orders of magnitude lower than that for the parent compound. These large rate reductions result primarily from the loss of transition-state binding interactions due to the replacement of sugar hydroxy groups, and such interactions are estimated to contribute at least 16.7 kJ (4 kcal).mol-1 to binding at the 3, 4 and 6 positions and more than 33.5 kJ (8 kcal).mol-1 at the 2 position. The existence of a linear free-energy relationship between log(k(cat.)/K(m)) for these compounds and the logarithm of the first-order rate constant for their spontaneous hydrolysis demonstrates that electronic effects are also important and provides direct evidence for oxocarbonium ion character in the enzymic transition state. A covalent intermediate which turns over only extremely slowly (t1/2 = 45 h) accumulates during hydrolysis of the 2-deoxyfluorogalactoside, and kinetic parameters for its formation have been determined. This intermediate is nonetheless catalytically competent, since it re-activates much more rapidly in the presence of the transglycosylation acceptors methanol or glucose, thereby providing support for the notion of a covalent intermediate during hydrolysis of the parent substrates.},
	keywords = {ALPHA-D-GLUCOPYRANOSYL, D-GLUCOPYRANOSYL PHOSPHATES, ENZYME, GLYCOGEN-PHOSPHORYLASE, HYDROLYSIS, inhibitors, OLIGOSACCHARIDE, SITE, SPECIFICITY, SUBSTRATE},
	isbn = {0264-6021},
	url = {<Go to ISI>://A1992JN81500010},
	author = {McCarter, J. D. and Adam,Michael J. and Withers, S. G.}
}
