A novel post-translational modification of the peptide antibiotic subtilin: isolation and characterization of a natural variant from Bacillus subtilis A.T.C.C. 6633.

A variant of the peptide antibiotic subtilin has been isolated from Bacillus subtilis A.T.C.C. 6633, and its structure has been shown to be [N alpha-succinyl-Trp1]subtilin. The chemical structure of a fragment derived by tryptic hydrolysis of the variant is shown to be N alpha-succinyl-Trp-Lys by 1H and 13C n.m.r., fast-atom-bombardment m.s. and total chemical synthesis [N alpha-Succinyl-Trp1]-subtilin is produced later in the growth of the bacterium than is subtilin; reverse-phase h.p.l.c. analysis shows that after 24 h growth the ratio subtilin/[N alpha-succinyl-Trp1]subtilin is approx. 1:2. Although [N alpha-succinyl-Trp1]subtilin retains significant antibacterial activity, it is 10-20 times less active than subtilin.