Proteomic Ligandability Maps of Phosphorus(V) Stereoprobes Identify Covalent TLCD1 Inhibitors

• DOI: 10.1021/jacs.5c01944
• Publication Date: 2025-04-23T15:23:12Z
• Authors: Hayden A. Sharma; Michael Bielecki; Meredith A. Holm; Ty M. Thompson; Yue Yin; Jacob B. Cravatt; Timothy B. Ware; Alex Reed; Molhm Nassir; Tamara El-Hayek E...; Bruno Melillo; J. Fernando Bazan; Phil S. Baran; Benjamin F. Cravatt

Activity-based protein profiling (ABPP) of stereoisomerically defined sets electrophilic compounds ('stereoprobes') offers a versatile way to discover covalent ligands for proteins in native biological systems. Here we report the synthesis and chemical proteomic characterization stereoprobes bearing P(V)-oxathiaphospholane (OTP) reactive group. ABPP experiments identified numerous human cancer cells that showed stereoselective reactivity with OTP stereoprobes, confirmed several these liganding events recombinant proteins. engaging poorly characterized transmembrane TLCD1 impaired incorporation monounsaturated fatty acids into phosphatidylethanolamine lipids cells, lipidomic phenotype mirrored genetic disruption this protein. Using AlphaFold2, found structurally resembles ceramide synthase acid elongase families coenzyme A-dependent lipid processing enzymes. This structural similarity included conservation catalytic histidine residues, mutation which blocked stereoprobe remodeling activity TLCD1. Taken together, data indicate acts as acyltransferase function inhibitors enzymatic activity. Our findings thus illuminate how analysis can facilitate functional annotation inhibition key metabolic enzyme cells.