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Current Protein & Peptide Science

Editor-in-Chief

ISSN (Print): 1389-2037
ISSN (Online): 1875-5550

The Circular Bacteriocins Gassericin A and Circularin A

Author(s): Yasushi Kawai, Rober Kemperman, Jan Kok and Tadao Saito

Volume 5, Issue 5, 2004

Page: [393 - 398] Pages: 6

DOI: 10.2174/1389203043379549

Price: $65

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-aminoacid- leader sequence.

Keywords: circular bacteriocins, circularin a, gassericin a, lactobacillus gasseri


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