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KMID : 0613820100200060853
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Journal of Life Science
2010 Volume.20 No. 6 p.853 ~ p.860
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Inactivation of the DevS Histidine Kinase of Mycobacterium smegmatis by the Formation of the Intersubunit Disulfide Bond
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Lee Jin-Mok
Kim Min-Ju
Park Kwang-Jin
Ko In-Jeong
Oh Jeong-Il
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Abstract
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The DevSR two-component system is a major regulatory system involved in redox sensing in Mycobacterium smegmatis. The DevSR system consists of the DevS histidine kinase and its cognate DevR response regulator. When exposed to hypoxic conditions, the DevS histidine kinase is activated to phosphorylate the DevR response regulator, leading to the transcriptional activation of the DevR regulation. The ligand-binding state of the heme embedded in the N-terminal GAF domain of DevS determines the kinase activity of DevS. In this study, we demonstrated that the redox-responsive cysteine (C547) in the C-terminal kinase domain is involved in the redox-dependent control of DevS kinase activity. The formation of an intersubunit disulfide bond between the C547 residues in the presence of O₂ led to inactivation of DevS kinase activity. The reduction of the oxidized DevS with reductants such as β-mercaptoethanol and dithiothreitol resulted in the restoration of DevS kinase activity. It was demonstrated in vivo by complementation test that the substitution of C547 to alanine partially impaired the sensory function of DevS in M. smegmatis.
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KEYWORD
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Cysteine, DevSR two-component system, histidine kinase, mycobacteria, redox sensing
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