Biochemical and genetic characterization of coagulin, a new antilisterial bacteriocin in the pediocin family of bacteriocins, produced by Bacillus coagulans I-4

A plasmid-linked antimicrobial peptide, named coagulin, produced by Bacillu s coagulans I-4 has recently been reported (B. Hyronimus, C. Le Marrec and M. C. Urdaci, J. Appl. Microbiol. 85:42-50, 1998), In the present study, th e complete, unambiguous primary amino acid sequence of the peptide was obta ined by a combination of both N-terminal sequencing of purified peptide and the complete sequence deduced from the structural gene harbored by plasmid I-4. Data revealed that this peptide of 44 residues has an amino acid sequ ence similar to that described for pediocins AcH and PA-1, produced by diff erent Pediococcus acidilactici strains and 100% identical. Coagulin and ped iocin differed only by a single amino acid at their C terminus. Analysis of the genetic determinants revealed the presence, on the pI(4) DNA, of the e ntire 3.5-kb operon of four genes described for pediocin AcH and PA-1 produ ction. No extended homology was observed between pSMB74 from P, acidilactic i and pI(4) when analyzing the regions upstream and downstream of the opero n, An oppositely oriented gene immediately dowstream of the bacteriocin ope ron specifies a 474-amino-acid protein which shows homology to Mob-Pre (pla smid recombination enzyme) proteins encoded by several small plasmids extra cted from grampositive bacteria. This is the first report of a pediocin-lik e peptide appearing naturally in a non-lactic acid bacterium genus.