Salivaricin G32, a Homolog of the PrototypeStreptococcus pyogenesNisin-Like Lantibiotic SA-FF22, Produced by the Commensal SpeciesStreptococcus salivarius

[摘要] Salivaricin G32, a 2667 Da novel member of the SA-FF22 cluster of lantibiotics, has been purified and characterized fromStreptococcus salivariusstrain G32. The inhibitory peptide differs from theStreptococcus pyogenes—produced SA-FF22 in the absence of lysine in position 2. The salivaricin G32 locus was widely distributed in BLIS-producingS. salivarius, with 6 (23%) of 26 strains PCR-positive for the structural gene,slnA. As for most other lantibiotics produced byS. salivarius, the salivaricin G32 locus can be megaplasmid encoded. Another member of the SA-FF22 family was detected in twoStreptococcus dysgalactiaeof bovine origin, an observation supportive of widespread distribution of this lantibiotic within the genusStreptococcus. Since the inhibitory spectrum of salivaricin G32 includesStreptococcus pyogenes, its production byS. salivarius, either as a member of the normal oral microflora or as a commercial probiotic, could serve to enhance protection of the human host againstS. pyogenesinfection.

[学科分类] 微生物学和免疫学