Open AccessThe nitrogen‐fixing symbiotic bacterium Mesorhizobium loti has and expresses the gene encoding pyridoxine 4‐oxidase involved in the degradation of vitamin B 6
Author(s) -
Yuan Baiqiang,
Yoshikane Yu,
Yokochi Nana,
Ohnishi Kouhei,
Yagi Toshiharu
Publication year - 2004
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.1574-6968.2004.tb09537.x
Subject(s) - biochemistry , biology , pyridoxine , escherichia coli , oxidase test , rhizobium , enzyme , microbiology and biotechnology , gene
Abstract The gene product of mll6785 of a nitrogen‐fixing symbiotic bacterium Mesorhizobium loti MAFF303099 was identified as pyridoxine 4‐oxidase, the first enzyme in the vitamin B 6 ‐degradation pathway. The gene was cloned and ligated into pET‐21a(+). Escherichia coli BL21(DE3) was co‐transformed with the constructed plasmid plus pKY206 containing groESL genes encoding chaperonins. The overexpressed protein was purified to homogeneity by the ammonium sulfate fractionation and three chromatography steps. The enzymatic properties of the purified protein, such as K m values for pyridoxine (213 ± 19 μM) and oxygen (78 ± 10 μM), were compared to those of pyridoxine 4‐oxidase from two bacteria with known vitamin B 6 ‐degradation pathway. M. loti grown in a Rhizobium medium showed the enzyme activity. The results suggest that M. loti also contains the degradation pathway of vitamin B 6 .