title: Molecular cloning and sequencing of two phospho-beta-galactosidase I and II genes of Lactobacillus gasseri JCM1031 isolated from human intestine.
abstract: Lactobacillus (Lb.) gasseri JCM1031, which is classified into the B1 subgroup of the Lb. acidophilus group of lactic acid bacteria, characteristically produces two different phospho-beta-galactosidases (P-beta-gal) I and II in the same cytosol as reported in our previous papers [Biosci. Biotech. Biochem., 60, 139-141, 708-710 (1996)]. To clarify the functional and genetic properties of the two enzymes, the structural genes of P-beta-gal I and II were cloned and sequenced. The structural gene of P-beta-gal I had 1,446 bp, encoding a polypeptide of 482 amino acid residues. The structural gene of P-beta-gal II had 1,473 bp, encoding a polypeptide of 491 amino acid residues. The deduced relative molecular masses of 55,188 and 56,243 agreed well with the previous value obtained from the purified P-beta-gal I and II protein, respectively. Multiple alignment of the protein sequence of P-beta-gal I and II with those of P-beta-gals from 5 microorganisms had 30-35% identity on the amino acid level, but those with phospho-beta-glucosidases from 5 microorganisms had the relatively high identity of about 50%. Considering that this strain grows on lactose medium and shows no beta-galactosidase activity, and that purified P-beta-gal I and II can obviously hydrolyze o-nitrophenyl-beta-D-galactopyranoside 6-phosphate (substrate), and also the conservation of a cysteine residue in the molecule, the P-beta-gal I and II were each confirmed as a novel P-beta-gal enzyme.
authors.affiliation: Laboratory of Animal Products Chemistry, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan. tsaito@bios.tohoku.ac.jp
authors.forename: T
authors.initials: T
authors.lastname: Saito
authors.forename: M
authors.initials: M
authors.lastname: Suzuki
authors.forename: K
authors.initials: K
authors.lastname: Konno
authors.forename: H
authors.initials: H
authors.lastname: Kitazawa
authors.forename: Y
authors.initials: Y
authors.lastname: Kawai
authors.forename: T
authors.initials: T
authors.lastname: Itoh
authors.forename: Y
authors.initials: Y
authors.lastname: Kamio
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D015139:Blotting, Southern; D003001:Cloning, Molecular; D015342:DNA Probes / Q000737:chemistry; D004269:DNA, Bacterial / Q000737:chemistry; D004587:Electrophoresis, Agar Gel; D005798:Genes, Bacterial; D006026:Glycoside Hydrolases; D006801:Humans; D007422:Intestines / Q000382:microbiology*; D007527:Isoenzymes / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D007779:Lactobacillus acidophilus / Q000145:classification / Q000201:enzymology* / Q000235:genetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009598:Nitrophenylgalactosides / Q000737:chemistry; D015183:Restriction Mapping; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D001616:beta-Galactosidase / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification