A NOVEL POSTTRANSLATIONAL MODIFICATION OF THE PEPTIDE ANTIBIOTIC SUBTILIN - ISOLATION AND CHARACTERIZATION OF A NATURAL VARIANT FROM BACILLUS-SUBTILIS ATCC-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 H-1 and C-13 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.