Degradation of 3-chloro-2-methylpropionic acid by Xanthobacter sp. CIMW 99.
Both stereoisomers of 3-chloro-2-methylpropionic acid (CMPA) and its methyl esters (MeCMPA) serve as growth substrates for a bacterial isolate (Xanthobacter sp. CIMW 99) when supplied as sole source of carbon and energy. Biodegradation of DL-CMPA and DL-MeCMPA was shown to be via a common pathway; an initial, constitutive, esterase converted the methyl ester to the corresponding carboxylic acid. Further metabolism required the activation of CMPA involving a CoA-, ATP-, Mg(2+)-dependent chloroacyl-CoA synthetase. Most noteworthy, it was the product of this reaction (3-chloro-2-methylpropionyl-CoA) that underwent hydrolytic dehalogenation to give 3-hydroxy-2-methylpropionyl-CoA (3-hydroxyisobutyryl-CoA). Further biodegradation proceeded by the action of a dehydrogenase on the CoA derivative to give methylmalonate-CoA-semialdehyde. Cells of CIMW 99 also contained a stable, constitutive, highly active 3-hydroxyisobutyrate dehydrogenase that was specific for the L(+) isomer. However, evidence is presented suggesting that this enzyme was not involved in the catabolism of the chlorinated substrates.
Smith
M R
MR
Department of Food Science, Agricultural University, Wageningen, The Netherlands.
van den Tweel
W J
WJ
de Bont
J A
JA
D015094:3-Hydroxyacyl CoA Dehydrogenases / Q000378:metabolism; D000429:Alcohol Oxidoreductases / Q000378:metabolism; D000445:Aldehyde Oxidoreductases / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism; D001673:Biodegradation, Environmental; D004785:Environmental Pollutants / Q000378:metabolism*; D006088:Gram-Negative Aerobic Bacteria / Q000378:metabolism*; D050646:Methylmalonate-Semialdehyde Dehydrogenase (Acylating); D009243:NAD / Q000096:biosynthesis; D011422:Propionates / Q000378:metabolism*
D001426:Bacterial Proteins; D004785:Environmental Pollutants; D011422:Propionates; D009243:NAD; C074479:3-chloro-2-methylpropionic acid; D000429:Alcohol Oxidoreductases; D015094:3-Hydroxyacyl CoA Dehydrogenases; C021398:3-hydroxyisobutyrate dehydrogenase; D000445:Aldehyde Oxidoreductases; D050646:Methylmalonate-Semialdehyde Dehydrogenase (Acylating)