title: 4-Pyridoxolactonase from a symbiotic nitrogen-fixing bacterium Mesorhizobium loti: cloning, expression, and characterization.
abstract: 4-Pyridoxolactonase is involved in the degradation pathway for pyridoxine, a free form of vitamin B6. The gene (mlr6805) encoding the putative 4-pyridoxolactonase of nitrogen fixing symbiotic microorganism Mesorhizobium loti MAFF303099 has been identified based on the genome database. The gene was cloned and overexpressed in a cotransformant Escherichia coli cell. The recombinant enzyme was dimeric protein and contained one mole of Zn2+ per mole of subunit. The enzyme showed about 30% identity with various N-acylhomoserine lactone lactonases and metallo-beta-lactamases. The phylogram made with ClustalW shows that 4-pyridoxolactonase makes a cluster with Agrobacterium tumefaciens acyl-homoserine lactone lactonase. The alignment of amino acid sequences suggests that 4-pyridoxolactonase has three histidine residues probably involved in binding of Zn2+.
authors.affiliation: Department of Bioresources Science, Faculty of Agriculture, Kochi University, Monobe-Otsu 200, Nankoku, Kochi 783-8502, Japan.
authors.forename: Junichi
authors.initials: J
authors.lastname: Funami
authors.forename: Yu
authors.initials: Y
authors.lastname: Yoshikane
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Kobayashi
authors.forename: Nana
authors.initials: N
authors.lastname: Yokochi
authors.forename: Baiqiang
authors.initials: B
authors.lastname: Yuan
authors.forename: Kozo
authors.initials: K
authors.lastname: Iwasaki
authors.forename: Kouhei
authors.initials: K
authors.lastname: Ohnishi
authors.forename: Toshiharu
authors.initials: T
authors.lastname: Yagi
mesh_terms: D016960:Agrobacterium tumefaciens / Q000201:enzymology / Q000235:genetics; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D002265:Carboxylic Ester Hydrolases / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D008969:Molecular Sequence Data; D010802:Phylogeny; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D012230:Rhizobiaceae / Q000201:enzymology* / Q000235:genetics; D020539:Sequence Analysis, Protein; D015032:Zinc / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D021122:Protein Subunits; C050712:4-pyridoxolactonase; D002265:Carboxylic Ester Hydrolases; D015032:Zinc