S-glutathionylation proteome profiling reveals a crucial role of a thioredoxin-like protein in interspecies competition and cariogenecity of Streptococcus mutans
S-glutathionylation proteome profiling reveals a crucial role of a thioredoxin-like protein in interspecies competition and cariogenecity of Streptococcus mutans
复制标题
S-谷胱甘肽化蛋白质组分析揭示了硫氧还蛋白样蛋白在变形链球菌的种间竞争和致龋性中的关键作用。
DOI：
10.1371/journal.ppat.1008774
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发表时间：
2020-07-01
期刊：
影响因子：
6.7
通讯作者：
Zhou, Xuedong
中科院分区：
文献类型：
--
作者：
Li, Zhengyi;Zhang, Chenzi;Zhou, Xuedong
S-glutathionylation is an important post-translational modification (PTM) process that targets protein cysteine thiols by the addition of glutathione (GSH). This modification can prevent proteolysis caused by the excessive oxidation of protein cysteine residues under oxidative or nitrosative stress conditions. Recent studies have suggested that protein S-glutathionylation plays an essential role in the control of cell-signaling pathways by affecting the protein function in bacteria and even humans. In this study, we investigated the effects of S-glutathionylation on physiological regulation within Streptococcus mutans, the primary etiological agent of human dental caries. To determine the S-glutathionylated proteins in bacteria, the Cys reactive isobaric reagent iodoacetyl Tandem Mass Tag (iodoTMT) was used to label the S-glutathionylated Cys site, and an anti-TMT antibody-conjugated resin was used to enrich the modified peptides. Proteome profiling identified a total of 357 glutathionylated cysteine residues on 239 proteins. Functional enrichment analysis indicated that these S-glutathionylated proteins were involved in diverse important biological processes, such as pyruvate metabolism and glycolysis. Furthermore, we studied a thioredoxin-like protein (Tlp) to explore the effect of S-glutathionylation on interspecies competition between oral streptococcal biofilms. Through site mutagenesis, it was proved that glutathionylation on Cys41 residue of Tlp is crucial to protect S. mutans from oxidative stress and compete with S. sanguinis and S. gordonii. An addition rat caries model showed that the loss of S-glutathionylation attenuated the cariogenicity of S. mutans. Taken together, our study provides an insight into the S-glutathionylation of bacterial proteins and the regulation of oxidative stress resistance and interspecies competition.Author summary S-glutathionylation is involved in many physiological processes such as antioxidation, detoxification and cell proliferation. However, the proteomics research on S-glutathionylation has never been performed in bacteria. The identification of and functional studies on glutathione reductase, glutathione synthesis dual-functional enzyme and glutathione-S-transferase in Streptococcus mutans, the main causative agent of dental caries, inspired the existence of complete S-glutathionylation system in this type of bacteria. It may impact various crucial physiological processes by regulating the function of modified proteins. Here, we explored the entire S-glutathionylation proteome through high-specific labeling and high-sensitivity mass spectrometry technologies. The results showed that about 11.7% of the total S. mutans proteins were S-glutathionylated, which indicated that S-glutathionylation plays a fundamental role in the regulation of cellular processes. Through functional analysis and domain prediction, we next uncovered a potential thioredoxin that contains two modified cysteines on its key active motif; S-glutathionylation of the sites affected the oxidative resistance, competition and cariogenecity of S. mutans. We anticipate that S-glutathionylation proteome studies could be performed on more refractory infectious diseases, revealing more mechanisms of pathogen infection and providing new methods to treat infectious diseases.
