S. G. Withers

Conformational changes induced by binding of UDP-2F-galactose to alpha-1,3 galactosyltransferase - Implications for catalysis (vol 369, pg 1270, 2007) (2008)

Jamaluddin, H., Tumbale, P., Withers, S. G., Acharya, K. R., Brew, K.

Conformational changes induced by binding UDP-2F-galactose to alpha-1,3-galactosyltransferase - Implications for catalysis (2007)

Jamaluddin, H., Tumbale, P., Withers, S. G., Acharya, K. R., Brew, K.

Structural and kinetic analysis of two covalent sialosyl-enzyme intermediates on trypanosoma rangeli sialidase (2006)

Watts, A. G., Oppezzo, P., Withers, S. G., Alzari, P. M., Buschiazzo, A.

Using substrate engineering to harness enzymatic promiscuity and expand biological catalysis (2006)

Lairson, L. L., Watts, A.G., Wakarchuk, W. W., Withers, S. G.

Glycosynthase-catalysed formation of modified polysaccharide microstructures (2004)

Watts, A. G., Withers, S. G.

The synthesis of some mechanistic probes for sialic acid processing enzymes and the labeling of a sialidase from Trypanosoma rangeli (2004)

Watts, A. G., Withers, S. G.

Structural analysis of the sialyltransferase CstII from Campylobacter jejuni in complex with a substrate analog (2004)

Chiu, C. P. C., Watts, A. G., Lairson, L. L., Gilbert, M., Lim, D., Wakarchuk, W. W., ...

Structural insights into the catalytic mechanism of trypanosoma cruzi trans -sialidase (2004)

Amaya, M. F., Watts, A. G., Damager, I., Wehenkel, A., Nguyen, T., Buschiazzo, A., ...

Family 39 a-L-iduronidases and b-D-xylosidases react through similar glycosyl-enzyme intermediates: Identification of the human iduronidase nucleophile (2003)

Nieman, C. E., Wong, A. W., He, S., Clarke, L., Hopwood, J. J., Withers, S. G.

Family 39 a-L-iduronidases and b-D-xylosidases react through similar glycosyl-enzyme intermediates: Identification of the human iduronidase nucleophile (2003)

Nieman, C. E., Wong, A. W., He, S., Clarke, L., Hopwood, J. J., Withers, S. G.

Trypanosoma cruzi Trans-sialidase operates through a covalent sialyl-enzyme intermediate: tyrosine is the catalytic nucleophile (2003)

Watts, A. G., Damager, I., Amaya, M. L., Buschiazzo, A., Alzari, P. M., Frasch, A. C., ...

Catalysis by hen egg-white lysozyme proceeds via a covalent intermediate (2001)

Vocadlo, D.J., Davies, G.J., Laine, R., Withers, S.G.

Hen egg-white lysozyme (HEWL) was the first enzyme to have its three-dimensional structure determined by X-ray diffraction techniques. A catalytic mechanism, featuring a long-lived oxocarbenium-ion...

Catalysis by hen egg-white lysozyme proceeds via a covalent intermediate (2001)

Vocadlo, D.J., Davies, G.J., Laine, R., Withers, S.G.

Hen egg-white lysozyme (HEWL) was the first enzyme to have its three-dimensional structure determined by X-ray diffraction techniques. A catalytic mechanism, featuring a long-lived oxocarbenium-ion...

Catalysis by hen egg-white lysozyme proceeds via a covalent intermediate (2001)

Vocadlo, D.J., Davies, G.J., Laine, R., Withers, S.G.

Hen egg-white lysozyme (HEWL) was the first enzyme to have its three-dimensional structure determined by X-ray diffraction techniques. A catalytic mechanism, featuring a long-lived oxocarbenium-ion...

Catalysis by hen egg-white lysozyme proceeds via a covalent intermediate (2001)

Vocadlo, D.J., Davies, G.J., Laine, R., Withers, S.G.

Hen egg-white lysozyme (HEWL) was the first enzyme to have its three-dimensional structure determined by X-ray diffraction techniques1. A catalytic mechanism, featuring a long-lived oxocarbenium-ion...

The structure of human pancreatic {alpha}-amylase at 1.8 A resolution and comparisons with related enzymes (1995)

BRAYER, G. D., LUO, Y., WITHERS, S. G.

Multiple phosphate positions in the catalytic site of glycogen phosphorylase: Structure of the pyridoxal-5'-pyrophosphate coenzyme-substrate analog (1992)

SPRANG, S. R., MADSEN, N. B., WITHERS, S. G.

Binding energy and catalysis. Fluorinated and deoxygenated glycosides as mechanistic probes of Escherichia coli (lacZ) beta-galactosidase.

McCarter, J D, Adam, M J, Withers, S G

Kinetic parameters for the hydrolysis of a series of deoxy and deoxyfluoro analogues of 2',4'-dinitrophenyl beta-D-galactopyranoside by Escherichia coli (lacZ) beta-galactosidase have been determined...

Probing the ionization state of substrate alpha-D-glucopyranosyl phosphate bound to glycogen phosphorylase b.

Street, I P, Withers, S G

The ionization state of the substrate alpha-D-glucopyranosyl phosphate bound at the active site of glycogen phosphorylase has been probed by a number of techniques. Values of Ki determined for a...

In vivo inhibition of beta-glucosidase and beta-mannosidase activity in rats by 2-deoxy-2-fluoro-beta-glycosyl fluorides and recovery of activity in vivo and in vitro.

McCarter, J D, Adam, M J, Hartman, N G, Withers, S G

2-Deoxy-2-fluoro-beta-glucosyl and -beta-mannosyl fluorides administered to rats in a single dose (10 mg/kg) inhibited beta-glucosidase and beta-mannosidase activity respectively after 1 h in brain,...

Kinetic mechanism and characterization of human beta-galactosidase precursor secreted by permanently transfected Chinese hamster ovary cells.

Zhang, S, McCarter, J D, Okamura-Oho, Y, Yaghi, F, Hinek, A, Withers, S G, ...

Chinese hamster ovary cell clones permanently transfected with the cDNA for human lysosomal beta-galactosidase secrete the enzyme precursor into the cell medium, from which it is purified to apparent...

The necessity of magnesium cation for acid assistance aglycone departure in catalysis by Escherichia coli (lacZ) beta-galactosidase.

Sinnott, M L, Withers, S G

1. Removal of Mg2+ from Escherichia coli (lacZ) beta-galactosidase slightly increases the rate of hydrolysis of galactosyl pyridinium salts, but decreases the rate of hydrolysis of arylgalactosides....

Substrate specificity of endoglucanase A from Cellulomonas fimi: fundamental differences between endoglucanases and exoglucanases from family 6.

Damude, H G, Ferro, V, Withers, S G, Warren, R A

Values of kcat. and Km for the hydrolysis of cellotetraose, cellotriose, beta-cellobiosyl fluoride and various beta-aryl cellobiosides by endoglucanase A (CenA) from Cellulomonas fimi indicate that...

Mechanistic consequences of replacing the active-site nucleophile Glu-358 in Agrobacterium sp. beta-glucosidase with a cysteine residue.

Lawson, S L, Warren, R A, Withers, S G

Retaining glycosidases achieve the hydrolysis of glycosidic bonds through the assistance of two key active-site carboxyls. One carboxyl functions as a nucleophile/leaving group, and the other acts as...

Salicortin: a repeat-attack new-mechanism-based Agrobacterium faecalis beta-glucosidase inhibitor.

Zhu, J, Withers, S G, Reichardt, P B, Treadwell, E, Clausen, T P

Salicortin, a natural product abundant in most members of the Salicaceae family, is a mechanism-based inactivator of Agrobacterium faecalis beta-glucosidase. Inactivation is delayed in the presence...

Crystal structure of the family 7 endoglucanase I (Cel7B) from Humicola insolens at 2.2 A resolution and identification of the catalytic nucleophile by trapping of the covalent glycosyl-enzyme intermediate.

MacKenzie, L F, Sulzenbacher, G, Divne, C, Jones, T A, Wöldike, H F, Schülein, M, ...

Cellulose is the major polysaccharide component of the plant cell wall and the most abundant naturally produced macromolecule on Earth. The enzymic degradation of cellulose, by cellulases, is...

Identification of glu-277 as the catalytic nucleophile of Thermoanaerobacterium saccharolyticum beta-xylosidase using electrospray MS.

Vocadlo, D J, MacKenzie, L F, He, S, Zeikus, G J, Withers, S G

Thermoanaerobacterium saccharolyticum beta-xylosidase is a member of family 39 of the glycosyl hydrolases. This grouping comprises both retaining beta-d-xylosidases and alpha-l-iduronidases. T....

Identification of Glu-120 as the catalytic nucleophile in Streptomyces lividans endoglucanase celB.

Zechel, D L, He, S, Dupont, C, Withers, S G

Streptomyces lividans CelB is a family-12 endoglucanase that hydrolyses cellulose with retention of anomeric configuration. A recent X-ray structure of the catalytic domain at 1.75 A resolution has...

Synthesis and kinetic evaluation of 4-deoxymaltopentaose and 4-deoxymaltohexaose as inhibitors of muscle and potato alpha-glucan phosphorylases.

Mosi, R, Withers, S G

alpha-Glucan phosphorylases degrade linear or branched oligosaccharides via a glycosyl transfer reaction, occurring with retention of configuration, to generate alpha-glucose-1-phosphate (G1P). We...

Identification of Glu-519 as the catalytic nucleophile in beta-mannosidase 2A from Cellulomonas fimi.

Stoll, D, He, S, Withers, S G, Warren, R A

Incubation of the beta-mannosidase Man2A from Cellulomonas fimi with 2-deoxy-2-fluoro-beta-D-mannosyl fluoride (2FMan beta F) resulted in time-dependent inactivation of the enzyme (inactivation rate...

Identification of the catalytic nucleophile of the Family 31 alpha-glucosidase from Aspergillus niger via trapping of a 5-fluoroglycosyl-enzyme intermediate.

Lee, S S, He, S, Withers, S G

The mechanism-based reagent 5-fluoro-alpha-d-glucopyranosyl fluoride (5F alpha GlcF) was used to trap a glycosyl-enzyme intermediate and identify the catalytic nucleophile at the active site of...

A solid-state 31P-NMR investigation of the allosteric transition in glycogen phosphorylase b.

Challoner, R, McDowell, C A, Stirtan, W, Withers, S G

The catalytic role of the cofactor phosphate moiety at the active site of glycogen phosphorylase has been the subject of many investigations including solution-state high-resolution 31P-NMR studies....

31P NMR relaxation studies of the activation of the coenzyme phosphate of glycogen phosphorylase. The role of motion of the bound phosphate.

Withers, S G, Madsen, N B, Sykes, B D

Spin-lattice and spin-spin relaxation rates (1/T1 and 1/T2) have been determined for the catalytically essential coenzyme phosphate at the active site of glycogen phosphorylase in both activated (R...

Binding energy and catalysis. Fluorinated and deoxygenated glycosides as mechanistic probes of Escherichia coli (lacZ) beta-galactosidase.

McCarter, J D, Adam, M J, Withers, S G

Kinetic parameters for the hydrolysis of a series of deoxy and deoxyfluoro analogues of 2',4'-dinitrophenyl beta-D-galactopyranoside by Escherichia coli (lacZ) beta-galactosidase have been determined...

Probing the ionization state of substrate alpha-D-glucopyranosyl phosphate bound to glycogen phosphorylase b.

Street, I P, Withers, S G

The ionization state of the substrate alpha-D-glucopyranosyl phosphate bound at the active site of glycogen phosphorylase has been probed by a number of techniques. Values of Ki determined for a...

In vivo inhibition of beta-glucosidase and beta-mannosidase activity in rats by 2-deoxy-2-fluoro-beta-glycosyl fluorides and recovery of activity in vivo and in vitro.

McCarter, J D, Adam, M J, Hartman, N G, Withers, S G

2-Deoxy-2-fluoro-beta-glucosyl and -beta-mannosyl fluorides administered to rats in a single dose (10 mg/kg) inhibited beta-glucosidase and beta-mannosidase activity respectively after 1 h in brain,...

Kinetic mechanism and characterization of human beta-galactosidase precursor secreted by permanently transfected Chinese hamster ovary cells.

Zhang, S, McCarter, J D, Okamura-Oho, Y, Yaghi, F, Hinek, A, Withers, S G, ...

Chinese hamster ovary cell clones permanently transfected with the cDNA for human lysosomal beta-galactosidase secrete the enzyme precursor into the cell medium, from which it is purified to apparent...

The necessity of magnesium cation for acid assistance aglycone departure in catalysis by Escherichia coli (lacZ) beta-galactosidase.

Sinnott, M L, Withers, S G

1. Removal of Mg2+ from Escherichia coli (lacZ) beta-galactosidase slightly increases the rate of hydrolysis of galactosyl pyridinium salts, but decreases the rate of hydrolysis of arylgalactosides....

Substrate specificity of endoglucanase A from Cellulomonas fimi: fundamental differences between endoglucanases and exoglucanases from family 6.

Damude, H G, Ferro, V, Withers, S G, Warren, R A

Values of kcat. and Km for the hydrolysis of cellotetraose, cellotriose, beta-cellobiosyl fluoride and various beta-aryl cellobiosides by endoglucanase A (CenA) from Cellulomonas fimi indicate that...

Mechanistic consequences of replacing the active-site nucleophile Glu-358 in Agrobacterium sp. beta-glucosidase with a cysteine residue.

Lawson, S L, Warren, R A, Withers, S G

Retaining glycosidases achieve the hydrolysis of glycosidic bonds through the assistance of two key active-site carboxyls. One carboxyl functions as a nucleophile/leaving group, and the other acts as...

Salicortin: a repeat-attack new-mechanism-based Agrobacterium faecalis beta-glucosidase inhibitor.

Zhu, J, Withers, S G, Reichardt, P B, Treadwell, E, Clausen, T P

Salicortin, a natural product abundant in most members of the Salicaceae family, is a mechanism-based inactivator of Agrobacterium faecalis beta-glucosidase. Inactivation is delayed in the presence...

Crystal structure of the family 7 endoglucanase I (Cel7B) from Humicola insolens at 2.2 A resolution and identification of the catalytic nucleophile by trapping of the covalent glycosyl-enzyme intermediate.

MacKenzie, L F, Sulzenbacher, G, Divne, C, Jones, T A, Wöldike, H F, Schülein, M, ...

Cellulose is the major polysaccharide component of the plant cell wall and the most abundant naturally produced macromolecule on Earth. The enzymic degradation of cellulose, by cellulases, is...

Identification of glu-277 as the catalytic nucleophile of Thermoanaerobacterium saccharolyticum beta-xylosidase using electrospray MS.

Vocadlo, D J, MacKenzie, L F, He, S, Zeikus, G J, Withers, S G

Thermoanaerobacterium saccharolyticum beta-xylosidase is a member of family 39 of the glycosyl hydrolases. This grouping comprises both retaining beta-d-xylosidases and alpha-l-iduronidases. T....

Identification of Glu-120 as the catalytic nucleophile in Streptomyces lividans endoglucanase celB.

Zechel, D L, He, S, Dupont, C, Withers, S G

Streptomyces lividans CelB is a family-12 endoglucanase that hydrolyses cellulose with retention of anomeric configuration. A recent X-ray structure of the catalytic domain at 1.75 A resolution has...

Synthesis and kinetic evaluation of 4-deoxymaltopentaose and 4-deoxymaltohexaose as inhibitors of muscle and potato alpha-glucan phosphorylases.

Mosi, R, Withers, S G

alpha-Glucan phosphorylases degrade linear or branched oligosaccharides via a glycosyl transfer reaction, occurring with retention of configuration, to generate alpha-glucose-1-phosphate (G1P). We...

Identification of Glu-519 as the catalytic nucleophile in beta-mannosidase 2A from Cellulomonas fimi.

Stoll, D, He, S, Withers, S G, Warren, R A

Incubation of the beta-mannosidase Man2A from Cellulomonas fimi with 2-deoxy-2-fluoro-beta-D-mannosyl fluoride (2FMan beta F) resulted in time-dependent inactivation of the enzyme (inactivation rate...

Identification of the catalytic nucleophile of the Family 31 alpha-glucosidase from Aspergillus niger via trapping of a 5-fluoroglycosyl-enzyme intermediate.

Lee, S S, He, S, Withers, S G

The mechanism-based reagent 5-fluoro-alpha-d-glucopyranosyl fluoride (5F alpha GlcF) was used to trap a glycosyl-enzyme intermediate and identify the catalytic nucleophile at the active site of...

A solid-state 31P-NMR investigation of the allosteric transition in glycogen phosphorylase b.

Challoner, R, McDowell, C A, Stirtan, W, Withers, S G

The catalytic role of the cofactor phosphate moiety at the active site of glycogen phosphorylase has been the subject of many investigations including solution-state high-resolution 31P-NMR studies....

31P NMR relaxation studies of the activation of the coenzyme phosphate of glycogen phosphorylase. The role of motion of the bound phosphate.

Withers, S G, Madsen, N B, Sykes, B D

Spin-lattice and spin-spin relaxation rates (1/T1 and 1/T2) have been determined for the catalytically essential coenzyme phosphate at the active site of glycogen phosphorylase in both activated (R...

Multiple phosphate positions in the catalytic site of glycogen phosphorylase: structure of the pyridoxal-5'-pyrophosphate coenzyme-substrate analog.

Sprang, S. R., Madsen, N. B., Withers, S. G.

The three-dimensional structure of an R-state conformer of glycogen phosphorylase containing the coenzyme-substrate analog pyridoxal-5'-diphosphate at the catalytic site (PLPP-GPb) has been refined...

Approaches to labeling and identification of active site residues in glycosidases.

Withers, S. G., Aebersold, R.

Glycosidases play a key role in a number of biological processes and, as such, are of considerable clinical and biotechnological importance. Knowledge of the identifies of catalytically important...

The structure of human pancreatic alpha-amylase at 1.8 A resolution and comparisons with related enzymes.

Brayer, G. D., Luo, Y., Withers, S. G.

The structure of human pancreatic alpha-amylase has been determined to 1.8 A resolution using X-ray diffraction techniques. This enzyme is found to be composed of three structural domains. The...

Cloning, mutagenesis, and structural analysis of human pancreatic alpha-amylase expressed in Pichia pastoris.

Rydberg, E. H., Sidhu, G., Vo, H. C., Hewitt, J., Côte, H. C., Wang, Y., ...

Human pancreatic alpha-amylase (HPA) was expressed in the methylotrophic yeast Pichia pastoris and two mutants (D197A and D197N) of a completely conserved active site carboxylic acid were generated....

Analysis of the dynamic properties of Bacillus circulans xylanase upon formation of a covalent glycosyl-enzyme intermediate.

Connelly, G. P., Withers, S. G., McIntosh, L. P.

NMR spectroscopy was used to search for mechanistically significant differences in the local mobility of the main-chain amides of Bacillus circulans xylanase (BCX) in its native and catalytically...