Study On Lysine Succinylome In Deinococcus Radiodurans

Posttranslational modification(PTM)is a fundamental part of life that ensures that proteins function at the appropriate time and subcellular location.It plays a key role in maintaining protein stability or dynamics Succinylation is a novel PTM.Therefore,the succinylation of a lysine residue adds two negative charges,which causes the residue to change from +1 to-1.Increasing evidences suggest that the succinylation of lysine residues mainly regulates enzymes involved in the major metabolism pathway in both prokaryotic and eukaryotic cells.Despite the growing interest,the detailed mechanisms of lysine succinylation are still unclear.Deinococcus radiodurans is one of the most radioresistant organisms on earth and is famous for its robust resistance.A major goal in our study of protein succinylation is to explore its function in D.radiodurans.We used high-resolution liquid chromatography-mass spectrometry(LC-MS/MS)for qualitative proteomics to perform a global succinylation analysis of D.radiodurans and identified 492 succinylation sites in 270 proteins.Combined with the bioinformatic analysis,these succinylated proteins are involved in a variety of biological processes and pathways.Succinylated proteins in D.radiodurans are mainly located in cytoplasm and periplasm.The largest proportion of succinylated proteins was related to catalytic activity,followed by binding activity.The top enriched biological process of succinylated proteins was the metabolic process,the TCA cycle.We found that the succinylated enzymes involved in nucleic acid binding processing are enriched in D.radiodurans compared with their previously reported levels in other bacteria.The interaction networks of succinylated proteins showed that succinylation were closely related to the stress/damage response.Our mutagenesis studies indicated that lysine succinylation regulates the enzymatic activities of species-specific proteins PprI and DdrB both in vivo and in vitro,which belong to the radiation-desiccation response regulon.Together,these results provide insight into the role of lysine succinylation in the extreme resistance of D.radiodurans.