Zhang Bing, Gu Huawei, Yang Yantao, Bai Haonan, Zhao Chao, Si Meiru, Su Tao, Shen Xihui
State Key Laboratory of Crop Stress Biology for Arid Areas, College of Life Sciences, Northwest A&F University, Yangling, China.
Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, China.
Front Microbiol. 2019 Jul 2;10:1483. doi: 10.3389/fmicb.2019.01483. eCollection 2019.
is a model organism for human pathogens and . The study of peroxiredoxin is helpful for understanding the survival, pathogenic infection, and antibiotic resistance of its homologous species. Alkyl hydroperoxide reductase subunit C (AhpC) is an important peroxiredoxin involved in oxidative damage defense. Here, we report that AhpC exhibits broad specificity for peroxide substrates, including inorganic and organic peroxides and peroxynitrite. AhpC catalyzes the reduction of oxidants using the N-terminal conserved Cys57 as a peroxidatic Cys and the C-terminal conserved Cys171 and Cys173 as resolving Cys. These three conserved Cys residues play critical roles in the catalytic mechanism. AhpD directly interacts with AhpC as an electron donor, and the conserved Cys residues in active site of AhpD are important for AhpC reduction. AhpC is directly repressed by OxyR as shown by identifying the OxyR binding site in the promoter with a DNA binding assay. This work sheds light on the function of AhpC in the peroxides and peroxynitrite damage response in and homologous species.
是人类病原体和的模式生物。对过氧化物酶的研究有助于了解其同源物种的生存、致病性感染和抗生素抗性。烷基过氧化氢还原酶亚基C（AhpC）是一种参与氧化损伤防御的重要过氧化物酶。在此，我们报道AhpC对过氧化物底物具有广泛的特异性，包括无机和有机过氧化物以及过氧亚硝酸根。AhpC利用N端保守的半胱氨酸57作为过氧化物酶半胱氨酸，C端保守的半胱氨酸171和半胱氨酸173作为还原半胱氨酸来催化氧化剂的还原。这三个保守的半胱氨酸残基在催化机制中起关键作用。AhpD作为电子供体直接与AhpC相互作用，AhpD活性位点中的保守半胱氨酸残基对AhpC的还原很重要。通过DNA结合试验鉴定启动子中的OxyR结合位点表明，AhpC直接受OxyR抑制。这项工作揭示了AhpC在及其同源物种的过氧化物和过氧亚硝酸根损伤反应中的功能。
