Structure and mechanism of a bacterial beta-glucosaminidase having O-GlcNAcase activity.
O-GlcNAc is an abundant post-translational modification of serine and threonine residues of nucleocytoplasmic proteins. This modification, found only within higher eukaryotes, is a dynamic modification that is often reciprocal to phosphorylation. In a manner analogous to phosphatases, a glycoside hydrolase termed O-GlcNAcase cleaves O-GlcNAc from modified proteins. Enzymes with high sequence similarity to human O-GlcNAcase are also found in human pathogens and symbionts. We report the three-dimensional structure of O-GlcNAcase from the human gut symbiont Bacteroides thetaiotaomicron both in its native form and in complex with a mimic of the reaction intermediate. Mutagenesis and kinetics studies show that the bacterial enzyme, very similarly to its human counterpart, operates via an unusual 'substrate-assisted' catalytic mechanism, which will inform the rational design of enzyme inhibitors.
York Structural Biology Laboratory, Department of Chemistry, University of York, York Y010 5YW, UK.
Rebecca J
RJ
Dennis
Edward J
EJ
Taylor
Matthew S
MS
Macauley
Keith A
KA
Stubbs
Johan P
JP
Turkenburg
Samuel J
SJ
Hart
Gary N
GN
Black
David J
DJ
Vocadlo
Gideon J
GJ
Davies
D000118:Acetylglucosaminidase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D001439:Bacteroides / Q000201:enzymology* / Q000235:genetics / Q000472:pathogenicity; D001483:Base Sequence; D020134:Catalytic Domain; D003001:Cloning, Molecular; D018360:Crystallography, X-Ray; D004269:DNA, Bacterial / Q000235:genetics; D006596:Hexosaminidases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D051548:Histone Acetyltransferases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D008958:Models, Molecular; D009097:Multienzyme Complexes / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D011487:Protein Conformation; D011499:Protein Processing, Post-Translational; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013045:Species Specificity; D001619:beta-N-Acetylhexosaminidases
D004269:DNA, Bacterial; D009097:Multienzyme Complexes; D011994:Recombinant Proteins; D051548:Histone Acetyltransferases; D006596:Hexosaminidases; C110628:hexosaminidase C; D000118:Acetylglucosaminidase; D001619:beta-N-Acetylhexosaminidases