Production of Terminal Alkenes in Natural Product Biosynthesis: Structural Studies of Sulfotransferase and Thioesterase Didomains

Natural Products Biosynthesis;Biofuel;Polyketide Synthase;Sulfotransferase;Thioesterase;Haloalkane Dehalogenase;Biological Chemistry;Science;Biological Chemistry

McCarthy, Jennifer GehretXu, Zhaohui ;

University of Michigan

关键词: Natural Products Biosynthesis;    Biofuel;    Polyketide Synthase;    Sulfotransferase;    Thioesterase;    Haloalkane Dehalogenase;    Biological Chemistry;    Science;    Biological Chemistry;   

Others  :  https://deepblue.lib.umich.edu/bitstream/handle/2027.42/96041/jgehret_1.pdf?sequence=2&isAllowed=y

瑞士|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

This thesis investigates a generalized biosynthetic scheme to produce hydrocarbons and natural products with a terminal alkene.Tandem sulfotransferase (ST) and thioesterase (TE) domains sulfonate a β-hydroxy group (ST) and hydrolyze, decarboxylate, and eliminate sulfate (TE) from an acyl carrier protein (ACP)-linked substrate to produce a terminal alkene instead of the carboxylic acid or macrolactone expected from a TE domain.Tandem ST-TE domains occur in the gene cluster for biosynthesis of the natural product curacin A (CurM) and in seven other bacterial genomes.Five of these convert free fatty acids to terminal-alkene hydrocarbons by an olefin synthase (OLS).To understand this novel biosynthetic strategy, the ST and TE domains from CurM (from Moorea producens) and OLS (from Synechococcus sp. PCC 7002) were investigated.Structural and biochemical investigations showed how the CurM and OLS ST and TE domains vary from canonical ST and TE folds to perform chemistry unique to the terminal-alkene producing systems.The CurM and OLS enzymes are similar to each other in structure and activity, but also exhibit subtle differences in substrate specificity, structure, and catalytic efficiency.The tandem ST-TE system is a promising chemical tool for the generation of new molecules or in the production of hydrocarbons for biofuel.This thesis also includes structural and biochemical characterization of DmmA, an orphan haloalkane dehalogenase (HLD), originally annotated as CurN in the curacin pathway.DmmA has a larger active site than other studied HLDs and is a promising candidate for industrial applications for HLDs that act on larger substrates.