title: Predicted incorporation of non-native substrates by a polyketide synthase yields bioactive natural product derivatives.
abstract: The polyether ionophore monensin is biosynthesized by a polyketide synthase that delivers a mixture of monensins A and B by the incorporation of ethyl- or methyl-malonyl-CoA at its fifth module. Here we present the first computational model of the fifth acyltransferase domain (AT5mon ) of this polyketide synthase, thus affording an investigation of the basis of the relaxed specificity in AT5mon , insights into the activation for the nucleophilic attack on the substrate, and prediction of the incorporation of synthetic malonic acid building blocks by this enzyme. Our predictions are supported by experimental studies, including the isolation of a predicted derivative of the monensin precursor premonensin. The incorporation of non-native building blocks was found to alter the ratio of premonensins A and B. The bioactivity of the natural product derivatives was investigated and revealed binding to prenyl-binding protein. We thus show the potential of engineered biosynthetic polyketides as a source of ligands for biological macromolecules.
authors.affiliation: Department of Theoretical Chemistry, Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr (Germany).
authors.forename: Kenny
authors.initials: K
authors.lastname: Bravo-Rodriguez
authors.forename: Ahmed F
authors.initials: AF
authors.lastname: Ismail-Ali
authors.forename: Stephan
authors.initials: S
authors.lastname: Klopries
authors.forename: Susanna
authors.initials: S
authors.lastname: Kushnir
authors.forename: Shehab
authors.initials: S
authors.lastname: Ismail
authors.forename: Eyad K
authors.initials: EK
authors.lastname: Fansa
authors.forename: Alfred
authors.initials: A
authors.lastname: Wittinghofer
authors.forename: Frank
authors.initials: F
authors.lastname: Schulz
authors.forename: Elsa
authors.initials: E
authors.lastname: Sanchez-Garcia
mesh_terms: D000217:Acyltransferases / Q000737:chemistry; D001688:Biological Products / Q000138:chemical synthesis*; D019295:Computational Biology; D004926:Escherichia coli / Q000378:metabolism; D005285:Fermentation; D008314:Malonates / Q000737:chemistry; D008958:Models, Molecular; D008985:Monensin / Q000031:analogs & derivatives* / Q000138:chemical synthesis* / Q000494:pharmacology; D048630:Polyketide Synthases / Q000737:chemistry*; D011487:Protein Conformation; D013302:Streptomyces / Q000201:enzymology; D013379:Substrate Specificity
chemical_list: D001688:Biological Products; D008314:Malonates; D048630:Polyketide Synthases; D008985:Monensin; D000217:Acyltransferases
keywords: QM/MM; computational chemistry; free energy calculations; molecular dynamics; monensin; polyketide biosynthesis