NMR characterization of the interaction between the PUB domain of peptide:N-glycanase and ubiquitin-like domain of HR23

PUB domains are identified in several proteins functioning in the ubiquitin (Ub)–proteasome system and considered as p97-binding modules. To address the further functional roles of these domains, we herein characterized the interactions of the PUB domain of peptide:N-glycanase (PNGase) with Ub and Ub-like domain (UBL) of the proteasome shuttle factor HR23. NMR data indicated that PNGase-PUB exerts an acceptor preferentially for HR23–UBL, electrostatically interacting with the UBL surface employed for binding to other Ub/UBL motifs. Our findings imply that PNGase-PUB serves not only as p97-binding module but also as a possible activator of HR23 in endoplasmic reticulum-associated degradation mechanisms.Structured summary of protein interactionsPNGase binds to HR23A by affinity chromatography technology (View interaction)PNGase and HR23A bind by nuclear magnetic resonance (View interaction)PNGase and HR23B bind by nuclear magnetic resonance (View interaction)