Multi-domain O-GlcNAcase structures reveal allosteric regulatory mechanisms

TY - JOUR

T1 - Multi-domain O-GlcNAcase structures reveal allosteric regulatory mechanisms

AU - Hansen, Sara Basse

AU - Bartual, Sergio G.

AU - Yuan, Huijie

AU - Raimi, Olawale G.

AU - Gorelik, Andrii

AU - Ferenbach, Andrew T.

AU - Lytje, Kristian

AU - Pedersen, Jan Skov

AU - Drace, Taner

AU - Boesen, Thomas

AU - van Aalten, Daan M. F.

N1 - Publisher Copyright: © 2025. The Author(s).

PY - 2025/10/3

Y1 - 2025/10/3

N2 - Nucleocytoplasmic protein O-GlcNAcylation is a dynamic modification catalysed by O-GlcNAc transferase (OGT) and reversed by O-GlcNAc hydrolase (OGA), whose activities are regulated through largely unknown O-GlcNAc-dependent feedback mechanisms. OGA is a homodimeric, multi-domain enzyme containing a catalytic core and a pseudo-histone acetyltransferase (pHAT) domain. While a catalytic structure has been reported, the structure and function of the pHAT domain remain elusive. Here, we report a crystal structure of the Trichoplax adhaerens pHAT domain and cryo-EM data of the multi-domain T. adhaerens and human OGAs, complemented by biophysical analyses. Here, we show that the eukaryotic OGA pHAT domain forms catalytically incompetent, symmetric homodimers, projecting a partially conserved putative peptide-binding site. In solution, OGA exist as flexible multi-domain dimers, but catalytic core-pHAT linker interactions restrict pHAT positional range. In human OGA, pHAT movements remodel the active site environment through conformational changes in a flexible arm region. These findings reveal allosteric mechanisms through which the pHAT domain contributes to O-GlcNAc homeostasis.

AB - Nucleocytoplasmic protein O-GlcNAcylation is a dynamic modification catalysed by O-GlcNAc transferase (OGT) and reversed by O-GlcNAc hydrolase (OGA), whose activities are regulated through largely unknown O-GlcNAc-dependent feedback mechanisms. OGA is a homodimeric, multi-domain enzyme containing a catalytic core and a pseudo-histone acetyltransferase (pHAT) domain. While a catalytic structure has been reported, the structure and function of the pHAT domain remain elusive. Here, we report a crystal structure of the Trichoplax adhaerens pHAT domain and cryo-EM data of the multi-domain T. adhaerens and human OGAs, complemented by biophysical analyses. Here, we show that the eukaryotic OGA pHAT domain forms catalytically incompetent, symmetric homodimers, projecting a partially conserved putative peptide-binding site. In solution, OGA exist as flexible multi-domain dimers, but catalytic core-pHAT linker interactions restrict pHAT positional range. In human OGA, pHAT movements remodel the active site environment through conformational changes in a flexible arm region. These findings reveal allosteric mechanisms through which the pHAT domain contributes to O-GlcNAc homeostasis.

UR - https://www.scopus.com/pages/publications/105017646848

U2 - 10.1038/s41467-025-63893-2

DO - 10.1038/s41467-025-63893-2

M3 - Article

C2 - 41044083

SN - 2041-1723

VL - 16

JO - Nature Communications

JF - Nature Communications

M1 - 8828

ER -