1H, 15N, 13C backbone and Cβ resonance assignments for UBQLN1 UBA and UBAA domains

Abstract

UBQLN1 functions in autophagy and proteasome-mediated protein degradation. It contains an N-terminal ubiquitin-like domain (UBL), a C-terminal ubiquitin-associated domain (UBA), and a flexible central region which functions as a chaperone to prevent protein aggregation. Here, we report the ¹H, ¹⁵N, and ¹³C resonance assignments for the backbone (^NH, N, C’, Cα, and Hα) and sidechain Cβ atoms of the UBQLN1 UBA and an N-terminally adjacent segment called the UBA-adjacent domain (UBAA). We find a subset of the resonances corresponding to the UBAA to have concentration-dependent chemical shifts, likely due to self-association. We also find the backbone amide nitrogen of T572 to be shifted upfield relative to the average value for a threonine amide nitrogen, a phenomenon likely caused by T572 Hγ1 engagement in a hydrogen bond with adjacent backbone carbonyl atoms. The assignments described in this manuscript can be used to study the protein dynamics of the UBQLN1 UBA and UBAA as well as the interaction of these domains with other proteins.