Subtilin, a 32-amino acid peptide with potent antimicrobial activity, has been isolated from Bacillus subtilis ATCC6633. The chemical structure has been confirmed by the unambiguous sequence-specific assignment of its 1H NMR spectrum. Detailed NMR analysis revealed that subtilin is a rather flexible molecule; the only observed conformational contraints were those imposed by the cyclic structures created by the tanthionine and 3-methyllanthionine residues. These results suggest that in aqueous solution subtilin and the homologous peptide nisin have similar conformation.
