Step-Economic Synthesis of Biomimetic β-Ketopolyene Thioesters and Demonstration of Their Usefulness in Enzymatic Biosynthesis Studies.

Studies on the biosynthetic processing of polyene thioester intermediates are complicated by limited access to appropriate substrate surrogates. We present a step-economic synthetic access to biomimetic β-ketopolyene thioesters that is based on an Ir-catalyzed reductive Horner-Wadsworth-Emmons olefination. New β-ketotriene and pentaenethioates of pantetheine and -acetylcysteamine were exemplarily synthesized via short and concise routes.

An Unusual Fatty Acyl:Adenylate Ligase (FAAL)-Acyl Carrier Protein (ACP) Didomain in Ambruticin Biosynthesis.

The divinylcyclopropane (DVC) fragment of the ambruticins is proposed to be formed by a unique polyene cyclisation mechanism, in which the unusual didomain AmbG plays a key role. It is proposed to activate the branched thioester carboxylic acid resulting from polyene cyclisation and to transfer it to its associated acyl carrier protein (ACP). After oxidative decarboxylation, the intermediate is channelled back into polyketide synthase (PKS) processing.

Characterisation of the Broadly-Specific O-Methyl-transferase JerF from the Late Stages of Jerangolid Biosynthesis.

We describe the characterisation of the -methyltransferase JerF from the late stages of jerangolid biosynthesis. JerF is the first known example of an enzyme that catalyses the formation of a non-aromatic, cyclic methylenolether. The enzyme was overexpressed in and the cell-free extracts were used in bioconversion experiments.