title: The mll6786 gene encodes a repressor protein controlling the degradation pathway for vitamin B6 in Mesorhizobium loti.
abstract: Pyridoxine is converted to succinic semialdehyde, acetate, ammonia and CO(2)  through the actions of eight enzymes. The genes encoding the enzymes occur as a cluster on the chromosomal DNA of Mesorhizobium loti, a symbiotic nitrogen-fixing bacterium. Here, it was found that disruption of the mll6786 gene, which is located between the genes encoding the first and eighth enzymes of the pathway, caused constitutive expression of the eight enzymes. The protein encoded by the mll6786 gene is a member of the GntR family and is designated as PyrR. PyrR comprises 223 amino acid residues and is a dimeric protein with a subunit molecular mass of 25 kDa. The purified PyrR with a C-terminal His(6) -tag could bind to an intergenic 67-bp DNA region, which contains a palindrome sequence and a deduced promoter sequence, between the mll6786 and mlr6787 genes, encoding PyrR and AAMS amidohydrolase, respectively.
authors.affiliation: Faculty of Agriculture and Agricultural Science Program, Graduate School of Integral Arts and Science, Kochi University, Nankoku, Kochi, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Nagase
authors.forename: Andrew N
authors.initials: AN
authors.lastname: Mugo
authors.forename: Huy Nhat
authors.initials: HN
authors.lastname: Chu
authors.forename: Yu
authors.initials: Y
authors.lastname: Yoshikane
authors.forename: Kouhei
authors.initials: K
authors.lastname: Ohnishi
authors.forename: Toshiharu
authors.initials: T
authors.lastname: Yagi
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D015964:Gene Expression Regulation, Bacterial; D059128:Mesorhizobium / Q000235:genetics* / Q000378:metabolism*; D053858:Metabolic Networks and Pathways; D011736:Pyridoxine / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D011994:Recombinant Proteins; D012097:Repressor Proteins; D011736:Pyridoxine