title: O2- and NO-sensing mechanism through the DevSR two-component system in Mycobacterium smegmatis.
abstract: The DevS histidine kinase of Mycobacterium smegmatis contains tandem GAF domains (GAF-A and GAF-B) in its N-terminal sensory domain. The heme iron of DevS is in the ferrous state when purified and is resistant to autooxidation from a ferrous to a ferric state in the presence of O(2). The redox property of the heme and the results of sequence comparison analysis indicate that DevS of M. smegmatis is more closely related to DosT of Mycobacterium tuberculosis than DevS of M. tuberculosis. The binding of O(2) to the deoxyferrous heme led to a decrease in the autokinase activity of DevS, whereas NO binding did not. The regulation of DevS autokinase activity in response to O(2) and NO was not observed in the DevS derivatives lacking its heme, indicating that the ligand-binding state of the heme plays an important role in the regulation of DevS kinase activity. The redox state of the quinone/quinol pool of the respiratory electron transport chain appears not to be implicated in the regulation of DevS activity. Neither cyclic GMP (cGMP) nor cAMP affected DevS autokinase activity, excluding the possibility that the cyclic nucleotides serve as the effector molecules to modulate DevS kinase activity. The three-dimensional structure of the putative GAF-B domain revealed that it has a GAF folding structure without cyclic nucleotide binding capacity.
authors: Department of Microbiology, Pusan National University, 609-735 Busan, South Korea.
authors: Jin-Mok
authors: JM
authors: Lee
authors: Ha Yeon
authors: HY
authors: Cho
authors: Hyo Je
authors: HJ
authors: Cho
authors: In-Jeong
authors: IJ
authors: Ko
authors: Sae Woong
authors: SW
authors: Park
authors: Hyung-Suk
authors: HS
authors: Baik
authors: Jee-Hyun
authors: JH
authors: Oh
authors: Chi-Yong
authors: CY
authors: Eom
authors: Young Min
authors: YM
authors: Kim
authors: Beom Sik
authors: BS
authors: Kang
authors: Jeong-Il
authors: JI
authors: Oh
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism*; D018360:Crystallography, X-Ray; D000242:Cyclic AMP / Q000378:metabolism; D006152:Cyclic GMP / Q000378:metabolism; D005296:Ferrous Compounds / Q000378:metabolism; D006418:Heme / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D020102:Mycobacterium smegmatis / Q000502:physiology*; D009569:Nitric Oxide / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism*; D010766:Phosphorylation; D006656:Protamine Kinase / Q000737:chemistry* / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D015398:Signal Transduction; D014451:Ubiquinone / Q000378:metabolism; D024482:Vitamin K 2 / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D005296:Ferrous Compounds; D024482:Vitamin K 2; D014451:Ubiquinone; D009569:Nitric Oxide; D006418:Heme; D000242:Cyclic AMP; C506260:DevS protein, Mycobacterium tuberculosis; D006656:Protamine Kinase; D006152:Cyclic GMP; D010100:Oxygen