Open AccessThe mll6786 gene encodes a repressor protein controlling the degradation pathway for vitamin B 6 in M esorhizobium loti
Author(s) -
Nagase Takayuki,
Mugo Andrew N.,
Chu Huy Nhat,
Yoshikane Yu,
Ohnishi Kouhei,
Yagi Toshiharu
Publication year - 2012
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2012.02510.x
Subject(s) - amidohydrolase , gene , biochemistry , biology , enzyme , gene cluster , repressor , mesorhizobium , genetics , microbiology and biotechnology , gene expression , bacteria , rhizobia , symbiosis
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 M esorhizobium 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 G nt R 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 H is 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.