Ubiquitin (Ub) is a post-translational modifier crucial to eukaryotic biology. The Ub system relays an intricate control over cellular processes through its attachment and detachment on substrate protein lysine residue, giving rise to a “ubiquitin code”. Deregulation in this code has severe consequences, primarily in disease pathogenesis. Proteolytic deubiquitinating enzymes (Dubs) render this PTM reversible by removing or “trimming” Ub off substrate protein. In turn, this interplay between the attachment and detachment machineries establishes a well-defined niche of ubiquitinated protein to relay critical cellular information. Ub modification, unlike other PTMs, is multivalent. Subsequent additions of one Ub moiety to 1 of 8 amines (Met1, Lys6, Lys11, Lys27, Lys29, Lys33, Lys48 and Lys68) on another confers the assembly of polyUb chains with well-defined linkages, each relaying a vastly different function. Dubs must recognize this multivalency by accommodating several topologies of Ub chains. Here we show that genetically encoded photophore Bpa in the Thr-9 position serves as a pan-Dub probe that gives insight into Ub binding sites. We demonstrate that genetic code expansion (GCE) coupled with liquid chromatography tandem mass spectrometry (LC-MS/MS) gives structural insight into the Ub-Dub interaction mode.

Structure-guided photoaffinity ubiquitin probes give insight into deubiquitinase binding sites

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.