Fig. 6
CMPS catalysis in tandem with an alkylmalonyl-CoA synthetase. a Incubation of 4-methyl-l-GHP and (2S)-alkylmalonyl-CoA (produced by Ccr)32,33, for selective formation of (4S,6R)-disubstituted-t-CMP derivatives. b Incubation of 4-methyl-l-GHP and (2R)-alkylmalonyl-CoA, produced by MatB catalysis from achiral alkylmalonic acids24,34, for selective formation of (4S,6S)-disubstituted-t-CMP derivatives. Note that CMPS-catalysed decarboxylation of (2S)-alkylmalonyl-CoA (a) is proposed to give the (Z)-enolate, while (2R)-alkylmalonyl-CoA (b) gives the (E)-enolate25. c Methoxymalonyl-CoA formation as catalysed by MatB and its one-pot reaction with 4-methyl-l-GHP, as catalysed by a CMPS to give the three shown stereoisomers. We propose that the nascent methoxymalonyl-CoA product of MatB catalysis is either epimeric or has the (2R)-stereochemistry, analogous to other MatB reactions (as in c)24,34, but undergoes relatively rapid epimerisation, consistent with the observed t-CMP products
