Stereochemistry of the conversion of methacrylate to β-hydroxyisobutyrate in Pseudomonas putida

Abstract

Stereospecifically labelled (2S,3S+ 2R,3R)-[2,3-²H₂]-β-hydroxyisobutyric acid methyl ester benzoate was synthesized and used to assign the Eu(fod)₃ shifted n.m.r. signals of the C-3 hydrogens of the unlabelled analogue. (E)-[3-²H₁]Methacrylic acid was converted by Pseudomonas putida(ATCC 21244) to (2S,3S)-[3-²H₁]-β-hydroxyisobutyric acid. The results show that the hydration of methacrylate to S-(+)-β-hydroxyisobutyric acid in this organism, probably via methacrylyl-CoA, proceeds stereospecifically by syn hydration.