Abstract
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.
Publication types
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Acyl Coenzyme A / metabolism
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Base Sequence
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Coenzyme A / metabolism
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DNA, Bacterial / genetics
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Enoyl-CoA Hydratase / metabolism
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GTP Phosphohydrolases / metabolism
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Glyoxylates / metabolism*
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Methylmalonyl-CoA Mutase / metabolism
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Methylobacterium extorquens / genetics
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Methylobacterium extorquens / metabolism*
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Molecular Sequence Data
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Oxidoreductases / metabolism
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Oxidoreductases Acting on CH-CH Group Donors*
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Thiolester Hydrolases / metabolism
Substances
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Acyl Coenzyme A
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DNA, Bacterial
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Glyoxylates
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ethylmalonyl-coenzyme A
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methylsuccinyl-coenzyme A
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isobutyryl-coenzyme A
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methacrylyl-coenzyme A
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Oxidoreductases
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Oxidoreductases Acting on CH-CH Group Donors
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2-methylacyl-CoA dehydrogenase
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Thiolester Hydrolases
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3-hydroxyisobutyryl-CoA hydrolase
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GTP Phosphohydrolases
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Enoyl-CoA Hydratase
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Methylmalonyl-CoA Mutase
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glyoxylic acid
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Coenzyme A
Associated data
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GENBANK/AF416776
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GENBANK/AF416777
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GENBANK/AY054980