title: Engineering stereoselectivity of ThDP-dependent enzymes.
abstract: Thiamine diphosphate-dependent enzymes are broadly distributed in all organisms, and they catalyse a broad range of C-C bond forming and breaking reactions. Enzymes belonging to the structural families of decarboxylases and transketolases have been particularly well investigated concerning their substrate range, mechanism of stereoselective carboligation and carbolyase reaction. Both structurally different enzyme families differ also in stereoselectivity: enzymes from the decarboxylase family are predominantly R-selective, whereas those from the transketolase family are S-selective. In recent years a key focus of our studies has been on stereoselective benzoin condensation-like 1,2-additions. Meanwhile, several S-selective variants of pyruvate decarboxylase, benzoylformate decarboxylase and 2-succinyl-5-enolpyruvyl-6-hydroxy-3-cyclohexene-1-carboxylate (SEPHCHC) synthase as well as R-selective transketolase variants were created that allow access to a broad range of enantiocomplementary α-hydroxyketones and α,α'-dihydroxyketones. This review covers recent studies and the mechanistic understanding of stereoselective C-C bond forming thiamine diphosphate-dependent enzymes, which has been guided by structure-function analyses based on mutagenesis studies and from influences of different substrates and organic co-solvents on stereoselectivity.
authors.affiliation: Department of Chemistry, Christopher Ingold Laboratories, University College London, UK.
authors.forename: Helen C
authors.initials: HC
authors.lastname: Hailes
authors.forename: Dörte
authors.initials: D
authors.lastname: Rother
authors.forename: Michael
authors.initials: M
authors.lastname: Müller
authors.forename: Robert
authors.initials: R
authors.lastname: Westphal
authors.forename: John M
authors.initials: JM
authors.lastname: Ward
authors.forename: Jürgen
authors.initials: J
authors.lastname: Pleiss
authors.forename: Constantin
authors.initials: C
authors.lastname: Vogel
authors.forename: Martina
authors.initials: M
authors.lastname: Pohl
mesh_terms: D000818:Animals; D002262:Carboxy-Lyases / Q000378:metabolism*; D002384:Catalysis; D006801:Humans; D013237:Stereoisomerism; D013835:Thiamine Pyrophosphate / Q000737:chemistry* / Q000378:metabolism*; D014174:Transketolase / Q000378:metabolism*
chemical_list: D014174:Transketolase; D002262:Carboxy-Lyases; D013835:Thiamine Pyrophosphate
keywords: 2-hydroxypropiophenone; acetoin; acyloins; asymmetric synthesis; benzoin; catalysis; phenylacetylcarbinol; protein engineering; α,α′-dihydroxyketone; α-hydroxyketone