Development of a chemoproteomic platform to identify the sites of (homo)citrullination within complex proteomes

ABSTRACT: Citrullination and homocitrullination of arginine and lysine can significantly impact protein structure and function. Citrullination of arginine is an enzymatic modification catalyzed by the Protein Arginine Deiminases (PADs). Homocitrullination of lysine is a non-enzymatic modification that occurs in the presence of high concentrations of cyanate. Both post-translational modifications are elevated in Rheumatoid Arthritis (RA) and other inflammatory diseases. Moreover, autoantibodies targeting these PTMs are associated with the development of RA. Identifying arginine and lysine residues that are hypersensitive to these modifications is critical for deepening our understanding of the functional effects of (homo)citrullination. Current methods use phenylglyoxal-biotin for the protein-level identification of (homo)citrullinated proteins, however, this platform does not inform on the exact site of citrullination. Herein we describe the development of a desthiobiotin-phenylglyoxal (DB-PG) probe, which can be used to selectively enrich and subsequently release (homo)citrullinated peptides for the site-specific identification of (homo)citrullinated arginines and lysines. Coupled with TMT quantification, this method monitors citrullination in ~800 arginine residues and ranks ~1400 lysine residues by homocitrullination sensitivity. Projecting forward, this platform will enable the comprehensive analysis of (homo)citrullination in complex proteomes.

INSTRUMENT(S):

ORGANISM(S): Mus Musculus (mouse)

TISSUE(S): Cell Culture, Macrophage

SUBMITTER: Sarah Mann  

LAB HEAD: Eranthie Weerapana

PROVIDER: PXD069261 | Pride | 2026-03-10

REPOSITORIES: Pride