Glyoxylate regeneration pathway in the methylotroph Methylobacterium extorquens AM1.
Most serine cycle methylotrophic bacteria lack isocitrate lyase and convert acetyl coenzyme A (acetyl-CoA) to glyoxylate via a novel pathway thought to involve butyryl-CoA and propionyl-CoA as intermediates. In this study we have used a genome analysis approach followed by mutation to test a number of genes for involvement in this novel pathway. We show that methylmalonyl-CoA mutase, an R-specific crotonase, isobutyryl-CoA dehydrogenase, and a GTPase are involved in glyoxylate regeneration. We also monitored the fate of (14)C-labeled carbon originating from acetate, butyrate, or bicarbonate in mutants defective in glyoxylate regeneration and identified new potential intermediates in the pathway: ethylmalonyl-CoA, methylsuccinyl-CoA, isobutyryl-CoA, methacrylyl-CoA, and beta-hydroxyisobutyryl-CoA. A new scheme for the pathway is proposed based on these data.
Korotkova
Natalia
N
Department of Chemical Engineering, University of Washington, Seattle, Washington 98195-1750, USA.
Chistoserdova
Ludmila
L
Kuksa
Vladimir
V
Lidstrom
Mary E
ME
D000214:Acyl Coenzyme A / Q000378:metabolism; D001483:Base Sequence; D003065:Coenzyme A / Q000378:metabolism; D004269:DNA, Bacterial / Q000235:genetics; D004746:Enoyl-CoA Hydratase / Q000378:metabolism; D020558:GTP Phosphohydrolases / Q000378:metabolism; D006038:Glyoxylates / Q000378:metabolism*; D008765:Methylmalonyl-CoA Mutase / Q000378:metabolism; D020601:Methylobacterium extorquens / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010088:Oxidoreductases / Q000378:metabolism; D044925:Oxidoreductases Acting on CH-CH Group Donors; D013869:Thiolester Hydrolases / Q000378:metabolism
D000214:Acyl Coenzyme A; D004269:DNA, Bacterial; D006038:Glyoxylates; C102829:ethylmalonyl-coenzyme A; C102828:methylsuccinyl-coenzyme A; C050106:isobutyryl-coenzyme A; C035909:methacrylyl-coenzyme A; D010088:Oxidoreductases; D044925:Oxidoreductases Acting on CH-CH Group Donors; C038808:2-methylacyl-CoA dehydrogenase; D013869:Thiolester Hydrolases; C035908:3-hydroxyisobutyryl-CoA hydrolase; D020558:GTP Phosphohydrolases; D004746:Enoyl-CoA Hydratase; D008765:Methylmalonyl-CoA Mutase; C031150:glyoxylic acid; D003065:Coenzyme A