OxyR senses sulfane sulfur and activates the genes for its removal in Escherichia coli

• Main Authors: Ningke Hou, Zhenzhen Yan, Kaili Fan, Huanjie Li, Rui Zhao, Yongzhen Xia, Luying Xun, Huaiwei Liu
• Format: Article
• Language: English
• Published: Elsevier 2019-09-01
• Series: Redox Biology
• Online Access: http://www.sciencedirect.com/science/article/pii/S2213231719305579

Sulfane sulfur species including hydrogen polysulfide and organic persulfide are newly recognized normal cellular components, and they participate in signaling and protect cells from oxidative stress. Their production has been extensively studied, but their removal is less characterized. Herein, we showed that sulfane sulfur at high levels was toxic to Escherichia coli under both anaerobic and aerobic conditions. OxyR, a well-known regulator against H2O2, also sensed sulfane sulfur, as revealed via mutational analysis, constructed gene circuits, and in vitro gene expression. Hydrogen polysulfide modified OxyR at Cys199 to form a persulfide OxyR C199-SSH, and the modified OxyR activated the expression of thioredoxin 2 and glutaredoxin 1. The two enzymes are known to reduce sulfane sulfur to hydrogen sulfide. Bioinformatics analysis indicated that OxyR homologs are widely present in bacteria, including obligate anaerobic bacteria. Thus, the OxyR sensing of sulfane sulfur may represent a preserved mechanism for bacteria to deal with sulfane sulfur stress. Keywords: OxyR, Sulfane sulfur, Escherichia coli, Thioredoxin, Glutaredoxin