Molecular and biochemical characterization of the protein template controlling biosynthesis of the lipopeptide lichenysin

Lichenysins are surface-active lipopeptides with antibiotic properties prod uced nonribosomally by several strains of Bacillus licheniformis. Here, we report the cloning and sequencing of an entire 26.6-kb lichenysin biosynthe sis operon from B. licheniformis ATCC 10716, Three large open reading frame s coding for peptide synthetases, designated licA, licB (three modules each ), and licC (one module), could be detected, followed by a gene, licTE, cod ing for a thioesterase like protein. The domain structure of the seven iden tified modules, which resembles that of the surfactin synthetases SrfA-A to -C, showed two epimerization domains attached to the third and sixth modul es. The substrate specificity of the first, fifth, and seventh recombinant adenylation domains of LicA to -C (cloned and expressed in Escherichia coli ) was determined to be Gin, Asp, and Ile (with minor Val and Leu substituti ons), respectively. Therefore, we suppose that the identified biosynthesis operon is responsible for the production of a lichenysin variant,vith the p rimary amino acid sequence L-Gln-L-Leu-D-Leu-L-Val-L-Asp-D-Leu-L-Ile, with minor Leu and Val substitutions at the seventh position.