Simple peptide bacteriocins

The inability to obtain complete protein sequence analysis of purified bacteriocins has been reason to suspect the presence of N-blocked peptide sequences (34) or lantibiotic residues (14). Recently, Piard et al. (14) have shown from partial sequencing and composition analysis that lacticin 481, a broad spectrum bacteriocin produced by L. lactis 481, also contains lanthionine residues. The early widespread interest in nisin and nisin-producing strains had given the impression that lantibiotics may be characteristic of bacteriocins of lactic acid bacteria. However, recent studies with other LAB bacteriocins suggest that simple peptide bacteriocins may prevail among the LAB. 

Simple Peptide Bacteriocins. Interest in LAB bacteriocins has prompted the application of molecular analyses to identify the genetic and/or protein sequences of these compounds. Such efforts have demonstrated the absence of lanthionine-related residues in leucocin A-UAL 187 (22) and lactacin F (35), for which the first 13 and 25 amino acid residues, respectively, were determined by sequence analysis the absence of lanthionine-related residues was confirmed by composition analysis. Similarly, the entire 54- and 39-amino acid sequences of lactococcin A (15) and Gcxi (16a), respectively, were also obtained by direct sequencing. 

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