Authors: Elena Kasparyan Michael Richter Carola Dresen Lydia S Walter Georg Fuchs Finian J Leeper Tobias Wacker Susana L A Andrade Geraldine Kolter Martina Pohl Michael Müller
Publish Date: 2014/06/24
Volume: 98, Issue: 23, Pages: 9681-9690
Abstract
The intermolecular asymmetric Stetter reaction is an almost unexplored transformation for biocatalysts Previously reported thiamine diphosphate ThDPdependent PigD from Serratia marcescens is the first enzyme identified to catalyze the Stetter reaction of αβunsaturated ketones Michael acceptor substrates and αketo acids PigD is involved in the biosynthesis of the potent cytotoxic agent prodigiosin Here we describe the investigation of two new ThDPdependent enzymes SeAAS from Saccharopolyspora erythraea and HapD from Hahella chejuensis Both show a high degree of homology to the amino acid sequence of PigD 39 and 51 respectively The new enzymes were heterologously overproduced in Escherichia coli and the yield of soluble protein was enhanced by coexpression of the chaperone genes groEL/ES SeAAS and HapD catalyze intermolecular Stetter reactions in vitro with high enantioselectivity The enzymes possess a characteristic substrate range with respect to Michael acceptor substrates This provides support for a new type of ThDPdependent enzymatic activity which is abundant in various species and not restricted to prodigiosin biosynthesis in different strains Moreover PigD SeAAS and HapD are also able to catalyze asymmetric carbon–carbon bond formation reactions of aldehydes and αketo acids resulting in 2hydroxy ketonesThis work was supported by the Deutsche Forschungsgemeinschaft DFG in the scope of the Research Group FOR 1296 We are grateful to Prof Peter Leadlay University of Cambridge and Dr Wolfgang Hüttel AlbertLudwigsUniversität Freiburg for providing plasmid pL1SL2 and for helpful discussions The technical assistance of Fabrizio Bonina Volker Brecht Wolfgang Kornberger and Simon Waltzer AlbertLudwigsUniversität Freiburg is gratefully acknowledged We thank Dr Mostafa Zarei Center for Biological Systems Analysis Freiburg for MS determinations
Keywords: