Characterization of the polyspecific transferase of murine type I fatty acid synthase (FAS) and implications for polyketide synthase (PKS) engineering

Characterization of the polyspecific transferase of murine type I fatty acid synthase (FAS) and implications for polyketide synthase (PKS) engineering https://dx.doi.org/10.1021/acschembio.7b00718 Abstract Fatty acid synthases (FASs) and polyketide synthases (PKSs) condense acyl compounds to fatty acids and polyketides, respectively. Both, FASs and PKSs, harbor acyltransferases (ATs), which select substrates for condensation by β-ketoacyl synthases (KSs). Here, we present the structural and functional characterization of the polyspecific malonyl/acetyltransferase (MAT) of murine FAS. We assign kinetic constants for the transacylation of the native substrates, acetyl- and malonyl-CoA, and demonstrate the promiscuity of FAS to accept structurally and chemically diverse CoA-esters. X-ray structural data of the KS-MAT didomain in a malonyl-loaded state suggests a MAT-specific role of an active site arginine in transacylation. Owing to its enzymatic properties and its accessibility as a separate domain, MAT of murine FAS may serve as versatile tool for engineering PKSs to provide custom-tailored access to new polyketides that can be applied in antibiotic and antineoplastic therapy. Raw dataset for protein databank accession code (PDB) 5my0 http://dx.doi.org/10.2210/pdb5my0/pdbThis work was supported by a Lichtenberg grant of the Volkswagen Foundation to M.G. (grant number 85701). This project was further supported by the LOEWE program (Landes-Offensive zur Entwicklung wissenschaftlich-ökonomischer Exzellenz) of the state of Hesse and was conducted within the framework of the MegaSyn Research Cluster