title: Molecular cloning, identification and characterization of 2-methyl-3-hydroxypyridine-5-carboxylic-acid-dioxygenase-coding gene from the nitrogen-fixing symbiotic bacterium Mesorhizobium loti.
abstract: The gene (mlr6788) of a nitrogen-fixing symbiotic bacterium Mesorhizobium loti MAFF303099 has been identified as a gene coding for 2-methyl-3-hydroxypyridine-5-carboxylic acid dioxygenase (MHPCO), the seventh enzyme in degradation pathway I for pyridoxine, a free form of vitamin B(6). The gene was cloned and overexpressed in Escherichia coli cells co-transformed with chaperonin genes. The homogeneous recombinant enzyme showed similar enzymatic properties to the enzyme from Pseudomonas sp. MA-1. MHPCO was essential for the assimilation of pyridoxine in M. loti, but not for its growth in a nutrient-rich medium. From the infection experiment of a symbiotic plant Lotus japonicus with an M. loti mlr6788 gene disruptant, MHPCO was demonstrated to be dispensable for at least nodule formation on roots of seedlings in symbiosis.
authors.affiliation: Department of Bioresources Science, Faculty of Agriculture, Nankoku, Kochi 783-8502, Japan.
authors.forename: Baiqiang
authors.initials: B
authors.lastname: Yuan
authors.forename: Nana
authors.initials: N
authors.lastname: Yokochi
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: D003001:Cloning, Molecular / Q000379:methods; D004789:Enzyme Activation; D004795:Enzyme Stability; D004926:Escherichia coli / Q000502:physiology*; D000070116:Lotus / Q000382:microbiology / Q000502:physiology; D006899:Mixed Function Oxygenases / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D009586:Nitrogen Fixation / Q000502:physiology; D018517:Plant Roots / Q000382:microbiology* / Q000502:physiology*; D015202:Protein Engineering / Q000379:methods; D020560:Proteobacteria / Q000502:physiology*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D013559:Symbiosis / Q000502:physiology
chemical_list: D011994:Recombinant Proteins; D006899:Mixed Function Oxygenases; C019483:methylhydroxypyridine-carboxylate dioxygenase