Structures of human O-GlcNAcase and its complexes reveal a new substrate recognition mode.
Human O-GlcNAcase (hOGA) is the unique enzyme responsible for the hydrolysis of the O-linked β-N-acetyl glucosamine (O-GlcNAc) modification, an essential protein glycosylation event that modulates the function of numerous cellular proteins in response to nutrients and stress. Here we report crystal structures of a truncated hOGA, which comprises the catalytic and stalk domains, in apo form, in complex with an inhibitor, and in complex with a glycopeptide substrate. We found that hOGA forms an unusual arm-in-arm homodimer in which the catalytic domain of one monomer is covered by the stalk domain of the sister monomer to create a substrate-binding cleft. Notably, the residues on the cleft surface afford extensive interactions with the peptide substrate in a recognition mode that is distinct from that of its bacterial homologs. These structures represent the first model of eukaryotic enzymes in the glycoside hydrolase 84 (GH84) family and provide a crucial starting point for understanding the substrate specificity of hOGA, which regulates a broad range of biological and pathological processes.
Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin, USA.
Baobin
B
Li
Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin, USA.
Hao
0000-0001-6514-0352
H
Li
Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin, USA.
Lei
L
Lu
Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin, USA.
Jiaoyang
J
Jiang
D018360:Crystallography, X-Ray; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology; D006031:Glycosylation / Q000187:drug effects; D006801:Humans; D055503:Protein Multimerization / Q000187:drug effects; D017433:Protein Structure, Secondary; D013379:Substrate Specificity / Q000187:drug effects; D001619:beta-N-Acetylhexosaminidases / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000378:metabolism*
D004791:Enzyme Inhibitors; C110628:hexosaminidase C; D001619:beta-N-Acetylhexosaminidases