PURIFICATION AND PARTIAL AMINO-ACID-SEQUENCE OF PLANTARICIN-S, A BACTERIOCIN PRODUCED BY LACTOBACILLUS-PLANTARUM LPCO10, THE ACTIVITY OF WHICH DEPENDS ON THE COMPLEMENTARY ACTION OF 2 PEPTIDES

Plantaricin S, one of the two bacteriocins produced by Lactobacillus p lantarum LPCO10, which,vas isolated from a green-olive fermentation (R Jimenez-Diaz, R. M. Rios-Sanchez, M. Desmazeaud, J, L. Ruiz-Barba, an d J.-C. Piard, Appl. Environ. Microbiol. 59:1416-1424, 1993), has been purified to homogeneity by ammonium sulfate precipitation, by binding to SP-Sepharose fast-flow, phenyl-Sepharose CL-4B, and C-2/C-18 rever se-phase chromatographies. The purification resulted in a final yield of 91.6% and a 352,617-fold increase in the specific activity, The bac teriocin activity was associated with two distinct peptides, termed al pha and beta, which were separated by C-2/C-18 reverse-phase chromatog raphy. Although beta alone appeared to retain a trace of inhibitory ac tivity, the complementary action of both the alpha and beta peptides w as required for full bacteriocin activity, as judged by both the agar well diffusion and the microtiter plate assays, From the N-terminal en d, 26 and 24 amino acids residues of alpha and beta, respectively, wer e sequenced. Further attempts at sequencing revealed no additional ami no acids residues, suggesting that either modifications in the next am ino acid residue blocked the sequencing region or that the C-terminal end had been reached, The amino acid sequences of alpha and beta show no apparent homology to each other or to other bacteriocins purified f rom lactic acid bacteria.