Xu Huangwei, Xuan Guanhua, Liu Huaiwei, Xia Yongzhen, Xun Luying
State Key Laboratory of Microbial Technology, Shandong University, 72 Binhai Road, Qingdao 266237, China.
School of Molecular Biosciences, Washington State University, Pullman, WA 991647520, USA.
Antioxidants (Basel). 2021 Nov 6;10(11):1778. doi: 10.3390/antiox10111778.
Sulfane sulfur, including persulfide and polysulfide, is produced from the metabolism of sulfur-containing organic compounds or from sulfide oxidation. It is a normal cellular component, participating in signaling. In bacteria, it modifies gene regulators to activate the expression of genes involved in sulfur metabolism. However, to determine whether sulfane sulfur is a common signal in bacteria, additional evidence is required. The ubiquitous multiple antibiotic resistance regulator (MarR) family of regulators controls the expression of numerous genes, but the intrinsic inducers are often elusive. Recently, two MarR family members, MexR and MgrA, have been reported to sense sulfane sulfur. Here, we report that MarR, the prototypical member of the family, also senses sulfane sulfur to form one or two disulfide or trisulfide bonds between two dimers. Although the tetramer with two disulfide bonds does not bind to its target DNA, our results suggest that the tetramer with one disulfide bond does bind to its target DNA, with reduced affinity. An MarR-repressed mKate reporter is strongly induced by polysulfide in . Further investigation is needed to determine whether sulfane sulfur is a common signal of the family members, but three members sense cellular sulfane sulfur to turn on antibiotic resistance genes. The findings offer additional support for a general signaling role of sulfane sulfur in bacteria.
包括过硫化物和多硫化物在内的硫化氢由含硫有机化合物的代谢或硫化物氧化产生。它是一种正常的细胞成分，参与信号传导。在细菌中，它修饰基因调节因子以激活参与硫代谢的基因的表达。然而，要确定硫化氢是否是细菌中的常见信号，还需要更多证据。普遍存在的多药耐药调节因子（MarR）家族控制着众多基因的表达，但其内在诱导物往往难以捉摸。最近，有报道称MarR家族的两个成员MexR和MgrA能感知硫化氢。在此，我们报告该家族的原型成员MarR也能感知硫化氢，在两个二聚体之间形成一个或两个二硫键或三硫键。尽管具有两个二硫键的四聚体不与其靶DNA结合，但我们的结果表明具有一个二硫键的四聚体确实能与其靶DNA结合，只是亲和力降低。在[具体实验环境]中，受MarR抑制的mKate报告基因会被多硫化物强烈诱导。需要进一步研究以确定硫化氢是否是该家族成员的常见信号，但已有三个成员能感知细胞内的硫化氢来开启抗生素抗性基因。这些发现为硫化氢在细菌中的一般信号传导作用提供了更多支持。
