A novel copper-sensing two-component system for inducing Dsb gene expression in bacteria  

一个新的感应铜离子的双组分信号转导系统

作　　者：Liang Yu Qiao Cao Weizhong Chen Nana Yang Cai-Guang Yang Quanjiang Ji Min Wu Taeok Bae Lefu Lan 余梁;曹荞;陈未中;杨娜娜;杨财广;季泉江;吴敏;Taeok Bae;蓝乐夫(University of Chinese Academy of Sciences,Beijing 100049,China;State Key Laboratory of Drug Research,Shanghai Institute of Materia Medica,Chinese Academy of Sciences,Shanghai 201203,China;School of Physical Science and Technology,ShanghaiTech University,Shanghai 201210,China;Department of Biomedical Sciences,University of North Dakota,Grand Forks ND 58203-9037,USA;Department of Microbiology and Immunology,Indiana University School of Medicine-Northwest,Gary IN 46408,USA;School of Pharmaceutical Science and Technology,Hangzhou Institute for Advanced Study,University of Chinese Academy of Sciences,Hangzhou 310024,China;NMPA Key Laboratory for Testing Technology of Pharmaceutical Microbiology,Shanghai Institute for Food and Drug Control,Shanghai 201203,China)

机构地区：[1]University of Chinese Academy of Sciences,Beijing 100049,China [2]State Key Laboratory of Drug Research,Shanghai Institute of Materia Medica,Chinese Academy of Sciences,Shanghai 201203,China [3]School of Physical Science and Technology,ShanghaiTech University,Shanghai 201210,China [4]Department of Biomedical Sciences,University of North Dakota,Grand Forks ND 58203-9037,USA [5]Department of Microbiology and Immunology,Indiana University School of Medicine-Northwest,Gary IN 46408,USA [6]School of Pharmaceutical Science and Technology,Hangzhou Institute for Advanced Study,University of Chinese Academy of Sciences,Hangzhou 310024,China [7]NMPA Key Laboratory for Testing Technology of Pharmaceutical Microbiology,Shanghai Institute for Food and Drug Control,Shanghai 201203,China

出　　处：《Science Bulletin》2022年第2期198-212,M0004,共16页科学通报（英文版）

基　　金：supported by the National Key R&D Program of China(2016YFA0501503);the National Mega-project for Innovative Drugs of China(2019ZX09721001-004-003);the National Natural Science Foundation of China(31670136 31870127 and 81861138047);the Science and Technology Commission of Shanghai Municipality(19JC1416400);the State Key Laboratory of Drug Research(SIMM2003ZZ-03).

摘　　要：In nature, bacteria must sense copper and tightly regulate gene expression to evade copper toxicity. Here,we identify a new copper-responsive two-component system named DsbRS in the important human pathogen Pseudomonas aeruginosa;in this system, DsbS is a sensor histidine kinase, and DsbR, its cognate response regulator, directly induces the transcription of genes involved in protein disulfide bond formation(Dsb)(i.e., the dsbDEG operon and dsbB). In the absence of copper, DsbS acts as a phosphatase toward DsbR, thus blocking the transcription of Dsb genes. In the presence of copper, the metal ion directly binds to the sensor domain of DsbS, and the Cys82 residue plays a critical role in this process. The copperbinding behavior appears to inhibit the phosphatase activity of DsbS, leading to the activation of DsbR.The copper resistance of the dsbRS knock-out mutant is restored by the ectopic expression of the dsbDEG operon, which is a DsbRS major target. Strikingly, cognates of the dsbRS-dsbDEG pair are widely distributed across eubacteria. In addition, a DsbR-binding site, which contains the consensus sequence 5’-TTA-N8-TTAA-3’, is detected in the promoter region of dsbDEG homologs in these species. These findings suggest that the regulation of Dsb genes by DsbRS represents a novel mechanism by which bacterial cells cope with copper stress.铜是生物体所必需的一种微量元素,但过量的铜会产生毒性.在感染宿主的过程中,病原菌需感知外界铜离子(浓度)的变化来调节体内相关基因表达以维持自身生存.本文利用铜绿假单胞菌为研究模型,揭示了一个新的感应铜离子的双组分信号转导系统并命名其为DsbRS.在缺乏铜胁迫的生长条件下,双组分信号转导系统DsbRS中的组氨酸蛋白激酶DsbS具磷酸酯酶活性,抑制了应答调控蛋白DsbR的磷酸化激活.在铜胁迫的生长环境下,铜离子与DsbS的周质空间区域结合,导致DsbR的转录调节活性升高,极可能是由于DsbS的磷酸酯酶活性受到抑制所致.磷酸化的DsbR直接结合到dsbDEG操纵子(编码催化蛋白质二硫键形成的Dsb家族蛋白)的启动子区域并激活dsbDEG的表达来抵抗铜的毒性. DsbRS基因和dsbDEG的同源基因簇,以及相应的DsbR结合位点TTA-N8-TTAA,在细菌界中广泛分布.这些研究结果表明DsbRS对Dsb基因的转录调控是细菌应答铜胁迫的一种新的机制,为有效利用铜制剂抗细菌感染提供了新的切入点.

关 键 词：Pseudomonas aeruginosa Two-component system Disulfide bond formation Gene regulation Copper resistance 

分 类 号：Q935[生物学—微生物学]