title: DNA sequencing and homologous expression of a small peptide conferring immunity to gassericin A, a circular bacteriocin produced by Lactobacillus gasseri LA39.
abstract: Gassericin A, produced by Lactobacillus gasseri LA39, is a hydrophobic circular bacteriocin. The DNA region surrounding the gassericin A structural gene, gaaA, was sequenced, and seven open reading frames (ORFs) of 3.5 kbp (gaaBCADITE) were found with possible functions in gassericin A production, secretion, and immunity. The deduced products of the five consecutive ORFs gaaADITE have homology to those of genes involved in butyrivibriocin AR10 production, although the genetic arrangements are different in the two circular bacteriocin genes. GaaI is a small, positively charged hydrophobic peptide of 53 amino acids containing a putative transmembrane segment. Heterologous expression and homologous expression of GaaI in Lactococcus lactis subsp. cremoris MG1363 and L. gasseri JCM1131(T), respectively, were studied. GaaI-expressing strains exhibited at least sevenfold-higher resistance to gassericin A than corresponding control strains, indicating that gaaI encodes an immunity peptide for gassericin A. Comparison of GaaI to peptides with similar characteristics found in the circular bacteriocin gene loci is discussed.
authors.affiliation: Laboratory of Animal Products Chemistry, Biological Resource Science, Graduate School of Agricultural Science, Tohoku University, Aoba-ku, Sendai, Japan. ykawai@bios.tohoku.ac.jp
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Kawai
authors.forename: Joni
authors.initials: J
authors.lastname: Kusnadi
authors.forename: Rober
authors.initials: R
authors.lastname: Kemperman
authors.forename: Jan
authors.initials: J
authors.lastname: Kok
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Ito
authors.forename: Mikiko
authors.initials: M
authors.lastname: Endo
authors.forename: Kensuke
authors.initials: K
authors.lastname: Arakawa
authors.forename: Hideaki
authors.initials: H
authors.lastname: Uchida
authors.forename: Junko
authors.initials: J
authors.lastname: Nishimura
authors.forename: Haruki
authors.initials: H
authors.lastname: Kitazawa
authors.forename: Tadao
authors.initials: T
authors.lastname: Saito
mesh_terms: D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001430:Bacteriocins / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D024881:Drug Resistance, Bacterial; D023061:Gene Order; D007778:Lactobacillus / Q000187:drug effects* / Q000235:genetics; D053858:Metabolic Networks and Pathways; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D001430:Bacteriocins; D004269:DNA, Bacterial; C096679:gassericin A