title: Structure-based dissociation of a type I polyketide synthase module.
abstract: Individual modules of modular polyketide synthases (PKSs) such as 6-deoxyerythronolide B synthase (DEBS) consist of conserved, covalently linked domains separated by unconserved intervening linker sequences. To better understand the protein-protein and enzyme-substrate interactions in modular catalysis, we have exploited recent structural insights to prepare stand-alone domains of selected DEBS modules. When combined in vitro, ketosynthase (KS), acyl transferase (AT), and acyl carrier protein (ACP) domains of DEBS module 3 catalyzed methylmalonyl transfer and diketide substrate elongation. When added to a minimal PKS, ketoreductase domains from DEBS modules 1, 2, and 6 showed specificity for the beta-ketoacylthioester substrate, but not for either the ACP domain carrying the polyketide substrate or the KS domain that synthesized the substrate. With insights into catalytic efficiency and specificity of PKS modules, our results provide guidelines for constructing optimal hybrid PKS systems.
authors.affiliation: Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA.
authors.forename: Alice Y
authors.initials: AY
authors.lastname: Chen
authors.forename: David E
authors.initials: DE
authors.lastname: Cane
authors.forename: Chaitan
authors.initials: C
authors.lastname: Khosla
mesh_terms: D000215:Acylation; D001483:Base Sequence; D002384:Catalysis; D002855:Chromatography, Thin Layer; D017931:DNA Primers; D048630:Polyketide Synthases / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D017931:DNA Primers; D011994:Recombinant Proteins; D048630:Polyketide Synthases