Organization of echinomycin biosynthetic gene cluster and echinomycin biosynthetic pathway in <i>S. griseovariabilis</i>.

<p>(A) Scheme of the biosynthetic gene cluster of echinomycin in <i>S. griseovariabilis</i>. The transcription direction of each gene was indicated by arrow. <i>qui6</i> and <i>qui7</i> are NRPS genes encoding the NRPS responsible for biosynthesis of the NRP backbone of echinomycin. To clarify the domains contained in Qui6 and Qui7, the scheme of the protein products encoded by <i>qui6</i> and <i>qui7</i> were situated rightly below the corresponding genes. Since the transcription directions of both <i>qui6</i> and <i>qui7</i> were reversed, their protein products were also exhibited inversely. From N terminal to C terminal, the domains contained were C, A, M, T, C, A, M, T, TE in Qui6 and C, A, T, E, C, A, T in Qui7. C: condensation-domain; A: adenylation-domain; T: peptidyl carrier protein-domain; M: methylation-domain; E: epimerase-domain; TE: thioesterase-domain. (B) Echinomycin biosynthetic pathway in <i>S. griseovariabilis</i>. FabC was an ACP engaged in fatty acid biosynthesis and its encoding gene was outside the gene cluster.