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

► PUB domain of PNGase binds to HR23-UBL more preferentially than ubiquitin chains. ► 3D model of the PUB-UBL complex is presented based on NMR data. ► The PUB-UBL complex is mediated by electrostatic interactions. ► PUB binds the UBL surface involved in intramolecular interaction with HR23-UBA. ► PNGase-PUB could serve as a putative activator of HR23 in ERAD.