On the steric course of the adenosylcobalamin-dependent 2-methyleneglutarate mutase reaction in Clostridium barkeri.
The enzymatically active enantiomer of 3-methylitaconate in Clostridium barkeri has (R)-configuration. This was checked by fermentation of the racemate and reisolation of the (S)-enantiomer. In addition (R)-3-methylitaconate was synthesized by enzymatic isomerisation of 2,3-dimethylmaleate which was protonated at the Si-face. 2-Methylene[2-2H1]glutarate was synthesized via (R)-3-methyl[3-2H1]itaconate by brief incubation of 2,3-dimethylmaleate with a cell-free extract of Clostridium barkeri in 2H2O. The predominantly monodeuterated compound was oxidized to (S)-[2-2H1]succinate as analysed by circular dichroism. The results demonstrate that 2-methyleneglutarate mutase catalyses the reversible migration of an acryloyl residue from the alpha-carbon to the beta-carbon of propionate with inversion of configuration at the alpha-carbon.
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Buckel
D002851:Chromatography, High Pressure Liquid; D003013:Clostridium / Q000201:enzymology*; D003038:Cobamides / Q000494:pharmacology*; D005285:Fermentation; D008401:Gas Chromatography-Mass Spectrometry; D005977:Glutarates / Q000378:metabolism; D019751:Intramolecular Transferases; D007535:Isomerases / Q000378:metabolism*; D009904:Optical Rotation; D013237:Stereoisomerism; D013386:Succinates / Q000378:metabolism; D019802:Succinic Acid
D003038:Cobamides; D005977:Glutarates; D013386:Succinates; C048646:3-methylitaconate; C002172:2-methyleneglutaric acid; D019802:Succinic Acid; D007535:Isomerases; D019751:Intramolecular Transferases; C047997:2-methyleneglutarate mutase; C000913:cobamamide