Multifunctional Enzymes in Natural Product Biosynthesis

Abstract

This cumulative doctoral thesis encompasses five research articles focused on investigations of multifunctional enzymes in natural product biosynthesis. The primary focus of this research is on exploring protein-protein and protein-substrate interactions, which play a critical role in polyketide and non-ribosomal peptide biosynthetic pathways. A part of this research is about studies of PPTase-CP interactions, ketosynthase-substrate, and dehydratase-substrate specificities.<br /> An interesting contribution of this thesis is the detailed investigation into the development of fluorescent probes in monitoring PPTase-CP interactions. This provides a simple way to monitor the carrier proteins activation by PPTases. Additionally, this thesis investigated the substrate specificity of ketosynthase by using 13C-labeled substrates.<br /> Another key enzyme explored in this thesis is dehydratase, which plays an important role in the polyketide and fatty acid biosynthetic pathways. In order to investigate the dehydratase product configurations and substrate scope, isotopically labeled probes and various substrates were synthesized, which enabled detailed stereochemical investigations.<br /> Moreover, this thesis also investigates the bifunctional terpene synthase, geosmin synthase, and presents the total synthesis of all isomers of geosmin, along with the characterization of the new compound, isogeosmin, which is produced by geosmin synthase.<br /> All in all, this thesis provides a comprehensive and detailed investigations of multifunctional enzymes in natural products biosynthesis. It advances the understanding of the enzymatic processes involved in these essential biochemical pathways, offering new insights into the enyzme mechanisms that drive these reactions.