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'''STRUCTURE OF THE CLOSTRIDIUM PERFRINGENS NAGJ FAMILY 84 GLYCOSIDE HYDROLASE, A HOMOLOGUE OF HUMAN O-GLCNACASE IN COMPLEX WITH PUGNAC''' | '''STRUCTURE OF THE CLOSTRIDIUM PERFRINGENS NAGJ FAMILY 84 GLYCOSIDE HYDROLASE, A HOMOLOGUE OF HUMAN O-GLCNACASE IN COMPLEX WITH PUGNAC''' | ||
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[[Category: Rao, F V.]] | [[Category: Rao, F V.]] | ||
[[Category: Villa, F.]] | [[Category: Villa, F.]] | ||
[[Category: | [[Category: Carbohydrate]] | ||
[[Category: | [[Category: Family 84 glycoside hydrolase]] | ||
[[Category: | [[Category: Glycoside hydrolase]] | ||
[[Category: | [[Category: Hyaluronidase]] | ||
[[Category: | [[Category: Hydrolase]] | ||
[[Category: | [[Category: O-glcnac]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 21:39:22 2008'' | |||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | |||
Revision as of 21:39, 3 May 2008
STRUCTURE OF THE CLOSTRIDIUM PERFRINGENS NAGJ FAMILY 84 GLYCOSIDE HYDROLASE, A HOMOLOGUE OF HUMAN O-GLCNACASE IN COMPLEX WITH PUGNAC
OverviewOverview
O-linked N-acetylglucosamine (O-GlcNAc) modification of specific serines/threonines on intracellular proteins in higher eukaryotes has been shown to directly regulate important processes such as the cell cycle, insulin sensitivity and transcription. The structure, molecular mechanisms of catalysis, protein substrate recognition/specificity of the eukaryotic O-GlcNAc transferase and hydrolase are largely unknown. Here we describe the crystal structure, enzymology and in vitro activity on human substrates of Clostridium perfringens NagJ, a close homologue of human O-GlcNAcase (OGA), representing the first family 84 glycoside hydrolase structure. The structure reveals a deep active site pocket highly conserved with the human enzyme, compatible with binding of O-GlcNAcylated peptides. Together with mutagenesis data, the structure supports a variant of the substrate-assisted catalytic mechanism, involving two aspartic acids and an unusually positioned tyrosine. Insights into recognition of substrate come from a complex with the transition state mimic O-(2-acetamido-2-deoxy-D-glucopyranosylidene)amino-N-phenylcarbamate (Ki=5.4 nM). Strikingly, the enzyme is inhibited by the pseudosubstrate peptide Ala-Cys(-S-GlcNAc)-Ala, and has OGA activity against O-GlcNAcylated human proteins, suggesting that the enzyme is a suitable model for further studies into the function of human OGA.
About this StructureAbout this Structure
2CBJ is a Single protein structure of sequence from Clostridium perfringens. Full crystallographic information is available from OCA.
ReferenceReference
Structural insights into the mechanism and inhibition of eukaryotic O-GlcNAc hydrolysis., Rao FV, Dorfmueller HC, Villa F, Allwood M, Eggleston IM, van Aalten DM, EMBO J. 2006 Apr 5;25(7):1569-78. Epub 2006 Mar 16. PMID:16541109 Page seeded by OCA on Sat May 3 21:39:22 2008