Biosynthesis of bacitracin: I. Formation of bacitracin by a subcellular fraction of Bacillus licheniformis

Abstract

1.1. The formation of bacitracin by a subcellular fraction prepared from a strain of Bacillus licheniformis has been studied.2.2. Under the conditions described here, the formation of antibiotic was greatly decreased in the absence of cysteine. The single omission of any of the other amino acids which are constituents of bacitracin did not greatly affect the amount of antibiotic formed. In addition, no stimulatory effect of ATP for the reaction was observed.3.3. The antibiotic formed has been demonstrated to incorporate [35S]cystine and [14C]isoleucine actively, but [14C]lysine which is only contained in the cyclic peptide part of bacitracin very slightly.4.4. A possible explanation for these results is that the reactions carried out in the present system are mainly composed of the addition of cysteine and isoleucine to a peptide precursor of bacitracin.