title: Cloning and analysis of the L-lactate utilization genes from Streptococcus iniae.
abstract: The presence of lactate oxidase was examined in eight Streptococcus species and some related species of bacteria. A clone (pGR002) was isolated from a genomic library of Streptococcus iniae generated in Escherichia coli, containing a DNA fragment spanning two genes designated lctO and lctP. We show that these genes are likely to be involved in the L-lactic acid aerobic metabolism of this organism. This DNA fragment has been sequenced and characterized. A comparison of the deduced amino acid sequence of LctP protein demonstrated that the protein had significant homology with the L-lactate permeases of other bacteria. The amino acid sequence of the LctO protein of S. iniae also showed a strong homology to L-lactate oxidase from Aerococcus viridans and some NAD-independent lactate dehydrogenases, all belonging to the family of flavin mononucleotide-dependent alpha-hydroxyacid-oxidizing enzymes. Biochemical assays of the gene products confirm the identity of the genes from the isolated DNA fragment and reveal a possible role for the lactate oxidase from S. iniae. This lactate oxidase is discussed in relation to the growth of the organism in response to carbon source availability.
authors.affiliation: Department of Microbiology, Institute of Food Research, Reading Laboratory, Reading RG6 6BZ. Gibelloa@eucmax.sim.ucm.es
authors.forename: A
authors.initials: A
authors.lastname: Gibello
authors.forename: M D
authors.initials: MD
authors.lastname: Collins
authors.forename: L
authors.initials: L
authors.lastname: Domínguez
authors.forename: J F
authors.initials: JF
authors.lastname: Fernández-Garayzábal
authors.forename: P T
authors.initials: PT
authors.lastname: Richardson
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics*; D001711:Biotransformation; D003001:Cloning, Molecular; D029968:Escherichia coli Proteins; D005798:Genes, Bacterial; D005947:Glucose / Q000494:pharmacology; D019344:Lactic Acid / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000235:genetics*; D006899:Mixed Function Oxygenases / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D013291:Streptococcus / Q000235:genetics* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; C083722:LldP protein, E coli; D026901:Membrane Transport Proteins; D019344:Lactic Acid; D006899:Mixed Function Oxygenases; C021497:lactate 2-monooxygenase; D005947:Glucose