Structural insights into the substrate binding adaptability and specificity of human O-GlcNAcase

Baobin Li,Chia-Wei Hu,Jiaoyang Jiang,Hao Li

doi:10.1038/s41467-017-00865-1

Baobin Li, Chia-Wei Hu + Show 2 more

Open Access

https://doi.org/10.1038/s41467-017-00865-1

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Journal: Nature Communications	Publication Date: Sep 22, 2017
Citations: 43	License type: open-access

Affiliation: University of Wisconsin–Madison

Abstract

The O-linked β-N-acetyl glucosamine (O-GlcNAc) modification dynamically regulates the functions of numerous proteins. A single human enzyme O-linked β-N-acetyl glucosaminase (O-GlcNAcase or OGA) hydrolyzes this modification. To date, it remains largely unknown how OGA recognizes various substrates. Here we report the structures of OGA in complex with each of four distinct glycopeptide substrates that contain a single O-GlcNAc modification on a serine or threonine residue. Intriguingly, these glycopeptides bind in a bidirectional yet conserved conformation within the substrate-binding cleft of OGA. This study provides fundamental insights into a general principle that confers the substrate binding adaptability and specificity to OGA in O-GlcNAc regulation.

Highlights

The O-linked β-N-acetyl glucosamine (O-GlcNAc) modification dynamically regulates the functions of numerous proteins
A diverse array of cellular processes including signal transduction and gene expression are regulated by an essential O-linked β-N-acetyl glucosamine (O-GlcNAc) modification of proteins, termed O-GlcNAcylation[1]. This dynamic process is controlled by the balanced activities of two opposing human enzymes: O-GlcNAc transferase (OGT) that installs O-GlcNAc on serine and threonine residues[2, 3], and O-GlcNAcase (OGA) that hydrolyzes this modification[4]
These glycopeptides were derived from characterized O-GlcNAcylation sites in the proteins: (a) α-crystallin B chain (FPTSTSLSPFYLR);[9] (b) TAB1 (VPYSSAQS);[16] (c) ELK1 (FWSTLSPI);[9] and (d) Lamin B1 (KLSPSPSSRVTVS)[9] (Table 1)

Summary

Introduction

The O-linked β-N-acetyl glucosamine (O-GlcNAc) modification dynamically regulates the functions of numerous proteins. We report the structures of OGA in complex with each of four distinct glycopeptide substrates that contain a single O-GlcNAc modification on a serine or threonine residue. A diverse array of cellular processes including signal transduction and gene expression are regulated by an essential O-linked β-N-acetyl glucosamine (O-GlcNAc) modification of proteins, termed O-GlcNAcylation[1] This dynamic process is controlled by the balanced activities of two opposing human enzymes: O-GlcNAc transferase (OGT) that installs O-GlcNAc on serine and threonine residues[2, 3], and O-GlcNAcase (OGA) that hydrolyzes this modification[4]. We found that the p53 glycopeptide was tightly bound in the substrate-binding cleft through abundant contacts of GlcNAc in the OGA catalytic pocket, and via peptide side chain and backbone interactions with cleft surface residues. We aim to assess the generality of the substratebinding mode of OGA and to extend our understanding on the principle of OGA substrate recognition

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