Active site modification of the β-ketoacyl-ACP synthase FabF3 of Streptomyces coelicolor affects the fatty acid chain length of the CDA lipopeptidesElectronic supplementary information (ESI) available: Experimental details, MS data and bioassays. See DOI: 10.1039/c0cc03444d

Using site directed mutagenesis we altered an active site residue (Phe107) of the enzyme encoded by fabF3 ( SCO3248 ) in the Streptomyces coelicolor gene cluster required for biosynthesis of the calcium dependent antibiotics (CDAs), successfully generating two novel CDA derivatives comprising truncated (C4) lipid side chains and confirming that fabF3 encodes a KAS-II homologue that is involved in determining CDA fatty acid chain length. Active site modification of the enzyme encoded by fabF3 in S. coelicolor resulted in two novel calcium dependent antibiotic comprising truncated (C4) lipid side chains (bCDA4a and ebCDA4a). This suggests that fabF3 encodes a KAS-II enzyme that controls the CDA fatty acid chain length.