THE STRUCTURE OF THE LANTIBIOTIC LACTICIN-481 PRODUCED BY LACTOCOCCUS-LACTIS - LOCATION OF THE THIOETHER BRIDGES

The lantibiotic lacticin 481 is a bacteriocin produced by Lactococcus lactis ssp, lactis, This polypeptide contains 27 amino acids, includin g the unusual residues dehydrobutyrine and the thioether-bridging lant hionine and 3-methyllanthionine. Lacticin 481 belongs to a structurall y distinct group of lantibiotics, which also include streptococcin A-F F22, salivaricin A and variacin, Here we report the first complete str ucture of this type of lantibiotic. The exact location of the thioethe r bridges in lacticin 481 was determined by a combination of peptide c hemistry, mass spectrometry and NMR spectroscopy, showing connections between residues 9 and 14, 11 and 25, and 18 and 26.