title: Ligand specificity of MobR, a transcriptional regulator for the 3-hydroxybenzoate hydroxylase gene of Comamonas testosteroni KH122-3s.
abstract: MobR from Comamonas testosteroni KH122-3s is a member of the MarR family of transcriptional regulators and functions as a repressor for the mobA gene that encodes a 3-hydroxybenzoate 4-hydroxylase. 3-Hydroxybenzoate binds to MobR as a ligand, resulting in an efficient induction of mobA. Various 3-hydroxybenzoate analogues were examined for their inducibilities using the mobA::lacZ transcriptional fusion system. beta-Galactosidase was induced by the addition of 2,3-dihydroxybenzoate or 3,5-dihydroxybenzoate besides 3-hydroxybenzoate, suggesting that the hydroxyl group at position 3 is critical in addition to the carboxyl group on the aromatic ring. A gel mobility-shift assay also showed that MobR was released from the target DNA in the presence of these compounds. Circular dichroism studies demonstrated that MobR adopted two conformational states corresponding to the 3-hydroxybenzoate-bound and unbound forms. Other ligands also induced the structural change as well; however, the tertiary structures of converted forms were different from those by 3-hydroxybenzoate.
authors: Department of Bioscience, Nanobiotechnology Research Center, School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo 669-1337, Japan.
authors: Mariko
authors: M
authors: Yoshida
authors: Takeshi
authors: T
authors: Hiromoto
authors: Keiichi
authors: K
authors: Hosokawa
authors: Hiroshi
authors: H
authors: Yamaguchi
authors: Shinsuke
authors: S
authors: Fujiwara
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002942:Circular Dichroism; D020604:Comamonas testosteroni / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D062385:Hydroxybenzoates / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D007700:Kinetics; D008024:Ligands; D006899:Mixed Function Oxygenases / Q000235:genetics / Q000378:metabolism*; D015394:Molecular Structure; D019800:Phenol / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D011485:Protein Binding / Q000187:drug effects; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D012118:Resorcinols
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D062385:Hydroxybenzoates; D008024:Ligands; D011994:Recombinant Proteins; D012118:Resorcinols; C076950:alpha-resorcylic acid; C032948:3-hydroxybenzoic acid; D019800:Phenol; C009135:2,3-dihydroxybenzoic acid; D006899:Mixed Function Oxygenases; C021385:3-hydroxybenzoate-4-monooxygenase