Gene identification and characterization of the pyridoxine degradative enzyme 4-pyridoxic acid dehydrogenase from the nitrogen-fixing symbiotic bacterium Mesorhizobium loti MAFF303099.
The gene encoding 4-pyridoxic acid dehydrogenase was identified as mlr6792 in a chromosome of a nitrogen-fixing symbiotic bacterium Mesorhizobium loti MAFF303099. The enzyme is the fourth enzyme in the vitamin B(6) (pyridoxine)-degradation pathway I. The recombinant enzyme with a his-tag over-expressed in Escherichia coli cells was a membrane-bound protein, and purified to homogeneity. The enzyme was a monomeric protein with a molecular weight of 59,000, and a flavoprotein containing one mole of FAD per mole of subunit. The optimum pH and temperature, and K(m) for 4-pyridoxic acid were pH 8.5 and 30 degrees C, and 29 muM, respectively. The enzyme was a glucose-methanol-choline (GMC) family protein with two signature patterns, FAD-binding residues, a putative active site histidine residue and a probable transmembrane segment.
Ge
Fei
F
Department of Bioresources Science, Faculty of Agriculture, Kochi University, Nankoku, Kochi 783-8502, Japan.
Yokochi
Nana
N
Yoshikane
Yu
Y
Ohnishi
Kouhei
K
Yagi
Toshiharu
T
D000429:Alcohol Oxidoreductases / Q000032:analysis / Q000737:chemistry* / Q000235:genetics; D020561:Alphaproteobacteria / Q000201:enzymology*; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000032:analysis / Q000737:chemistry* / Q000235:genetics; D003001:Cloning, Molecular; D015870:Gene Expression; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D009586:Nitrogen Fixation; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013559:Symbiosis; D025101:Vitamin B 6 / Q000378:metabolism
D001426:Bacterial Proteins; D011994:Recombinant Proteins; D025101:Vitamin B 6; D000429:Alcohol Oxidoreductases; C038807:4-pyridoxic acid dehydrogenase