First evidence of production of the lantibiotic nisin P

Abstract

AbstractNisin P is a natural nisin variant, the genetic determinants for which were previously identified in the genomes of twoStreptococcusspecies, albeit with no confirmed evidence of production. Here we describeStreptococcus agalactiaeDPC7040, a human fecal isolate, which exhibits antimicrobial activity against a panel of gut and food isolates by virtue of producing nisin P. Nisin P was purified, and its predicted structure was confirmed by nanoLC-MS/MS, with both the fully modified peptide and a variant without rings B and E being identified. Additionally, we compared its spectrum of inhibition and minimum inhibitory concentration (MIC) with that of nisin A and its antimicrobial effect in a fecal fermentation in comparison with nisin A and H. We found that its antimicrobial activity was less potent than nisin A and H, and we propose a link between this reduced activity and the peptide structure.