Quantitative Site-specific Chemoproteomic Profiling of Protein Lipoylation

ABSTRACT: Protein lipoylation is an evolutionarily conserved post-translational modification (PTM) from prokaryotes and eukary-otes. Lipoylation is known to contribute to several human diseases including metabolic disorders, cancer and Alz-heimer’s disease. While individual lipoylated proteins have been biochemically studied, a strategy for globally quantify-ing lipoylation sites in proteomes is lacking. Herein we developed a butyraldehyde-alkynyl probe (BAP) to specifically label and enrich lipoylations in complexed biological samples. Combined with a chemoproteomic pipeline with cus-tomized tandem enzyme digestion protocols and a biotin enrichment tag with enhanced ionization, we successfully quantified all known lipoylation sites in both E. coli and human proteomes. The strategy enabled us to dissect the de-pendence of the three evolutionarily related lipoylation sites in dihydrolipoamide acetyltransferase (ODP2) in Esche-richia coli and evaluated the functional connection between the de novo lipoylation synthetic pathway and the salvage pathway. The study also led to the discovery that lipoate-protein ligase A (LplA) could replace octanoic acid transferase (LipB) to perform the function of transferring octanoic acid in the de novo synthetic pathway when octanoic acids are abundant. Our chemoproteomic platform provides a useful tool to monitor the state of lipoylation in proteome samples, which might help decipher molecular mechanisms of lipoylation-related diseases.

ORGANISM(S): Homo Sapiens Escherichia Coli

SUBMITTER: Chu Wang  

PROVIDER: PXD031466 | iProX | Sat Feb 05 00:00:00 GMT 2022

REPOSITORIES: iProX