title: Lysine racemase from a lactic acid bacterium, Oenococcus oeni: structural basis of substrate specificity.
abstract: Oenococcus oeni, a lactic acid bacterium, possesses a lysine racemase, which has a specific activity towards basic amino acids. A comparison of amino acid residues around the active site suggested that Ile222 and Tyr354 of the Geobacillus stearothermophilus alanine racemase, which shares 60% sequence similarity with lysine racemase, were replaced by Thr224 and Trp355 in the O. oeni lysine racemase. T224I/W355Y double mutations significantly decreased the activity of lysine racemase, whereas I222T/Y354W double mutations endowed alanine racemase with lysine racemization activity. These results suggest that the two residues play an important role in lysine racemization.
authors.affiliation: Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa-Ku, Nagoya, Aichi 464-8601, Japan.
authors.forename: Shiro
authors.initials: S
authors.lastname: Kato
authors.forename: Hisashi
authors.initials: H
authors.lastname: Hemmi
authors.forename: Tohru
authors.initials: T
authors.lastname: Yoshimura
mesh_terms: D000591:Amino Acid Isomerases / Q000737:chemistry* / Q000235:genetics; D019943:Amino Acid Substitution; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics; D020134:Catalytic Domain; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D007536:Isomerism; D007700:Kinetics; D008239:Lysine / Q000737:chemistry; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D056585:Oenococcus / Q000201:enzymology*; D017386:Sequence Homology, Amino Acid; D040681:Structural Homology, Protein; D013379:Substrate Specificity
chemical_list: D001426:Bacterial Proteins; D000591:Amino Acid Isomerases; C084211:lysine racemase; D008239:Lysine