H. Kimura et al., Purification and partial identification of bacteriocin ISK-1, a new lantibiotic produced by Pediococcus sp. ISK-1, BIOS BIOT B, 62(12), 1998, pp. 2341-2345
Bacteriocin ISK-1 is a proteinaceous inhibitory substance produced by Pedio
coccus sp. ISK-1 isolated from well-aged Nukadoko. Bacteriocin ISK-1 was pu
rified by acid treatment, ammonium sulfate precipitation, cation-exchange c
hromatography, and reversed-phase HPLC from the culture supernatant of Pedi
ococcus sp. ISK-1. Purification of bacteriocin ISK-1 resulted in a 30-fold
increase in the specific activity and the recovery was 17%. Molecular mass
of bacteriocin ISK-1 measured by fast atom bombardment-mass spectrometry wa
s 2,960. The amino acid composition analysis of bacteriocin ISK-1 showed th
at it contained unusual amino acids such as lanthionine and/or 3-methyllant
hionine, which is a characteristic of lantibiotics. The N-terminal amino ac
id sequence analysis indicated the first seven N-terminal amino acid residu
es as NH2-K-K-K-S-G-V-I. The primary sequence showed significant similarity
to the lantibiotics lacticin 481 from Lactococcus lactis and variacin from
Micrococcus varians, which suggests that bacteriocin ISK-1 is a novel lant
ibiotic belonging to a lacticin-481 type.