title: The circular bacteriocins gassericin A and circularin A.
abstract: Gassericin A, a bacteriocin produced by Lactobacillus gasseri LA39, shows antibacterial activity against a number of Gram-positive food-borne pathogenic bacteria. Circularin A produced by Clostridium beijerinckii ATCC25752 is active against C. tyrobutyricum, a known cheese-spoilage bacterium. Both bacteriocins were purified to homogeneity from culture supernatants by reverse-phase chromatography and the subsequently determined amino acid sequences were used to clone the bacteriocin structural genes. Mature gassericin A and circularin A are class V circular bacteriocins comprised of 58 and 69 amino acid residues, respectively. Both bacteriocins are resistant to several peptidases and proteases, as are other cyclic bacteriocins. Heterologous expression of gassericin A in Escherichia coli was used to produce a non-cyclic mature peptide, which was shown to have a specific activity 173-fold lower than the circular molecule. The minimal region for production and secretion of active circularin A is comprised of five genes, as was deduced by heterologous gene expression in Enterococcus faecalis. Gassericin A and circularin A have limited mutual similarity in their primary sequences. Unlike most bacteriocins, including gassericin A, circularin A has a three-amino-acid-leader sequence.
authors.affiliation: Laboratory of Animal Products Chemistry, Graduate School of Agricultural Science, Tohoku University, Sendai 981-8555, Japan. ykawai@bios.tohoku.ac.jp
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Kawai
authors.forename: Rober
authors.initials: R
authors.lastname: Kemperman
authors.forename: Jan
authors.initials: J
authors.lastname: Kok
authors.forename: Tadao
authors.initials: T
authors.lastname: Saito
mesh_terms: D000818:Animals; D001430:Bacteriocins / Q000096:biosynthesis* / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D046970:Clostridium beijerinckii / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D006801:Humans; D007778:Lactobacillus / Q000737:chemistry / Q000235:genetics; D010447:Peptide Hydrolases / Q000378:metabolism
chemical_list: D001430:Bacteriocins; C499036:circularin A; C096679:gassericin A; D010447:Peptide Hydrolases