First Succinyl-Proteome Profiling of Extensively Drug-Resistant <i>Mycobacterium tuberculosis</i> Revealed Involvement of Succinylation in Cellular Physiology

Protein
lysine succinylation, an emerging protein post-translational
modification widespread among eukaryotic and prokaryotic cells, represents
an important regulator of cellular processes. However, the extent
and function of lysine succinylation in Mycobacterium tuberculosis, especially extensively drug-resistant strain, remain elusive. Combining
protein/peptide prefractionation, immunoaffinity enrichment, and LC–MS/MS
analysis, a total of 686 succinylated proteins and 1739 succinylation
sites of M. tuberculosis were identified, representing
the first global profiling of M. tuberculosis lysine
succinylation. The identified succinylated proteins are involved in
a variety of cellular functions such as metabolic processes, transcription,
translation, and stress responses and exhibit different subcellular
localization via GO, protein interaction network, and other bioinformatic
analysis. Notably, proteins involved in protein biosynthesis and carbon
metabolism are preferred targets of lysine succinylation. Moreover,
two prevalent sequence patterns: EKsuc and K*****Ksuc, can be found around the succinylation sites. There are
109 lysine-succinylated homologues in E. coli, suggesting
highly conserved succinylated proteins. Succinylation was found to
occur at the active sites predicted by Prosite signature including
Rv0946c, indicating that lysine succinylation may affect their activities.
There is extensive overlapping between acetylation sites and succinylation
sites in M. tuberculosis. Many M. tuberculosis metabolic enzymes and antibiotic resistance proteins were succinylated.
This study provides a basis for further characterization of the pathophysiological
role of lysine succinylation in M. tuberculosis.