Microbial growth on C1 compounds. 3. Distribution of radioactivity in metabolites of methanol-grown <i>Pseudomonas</i> AM1 after incubation with [14C]methanol and [14C]bicarbonate

Large, Peter J.; Peel, David; Quayle, J. R.

doi:10.1042/bj0820483

Cited by 55 publications

(28 citation statements)

References 9 publications

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“…This showed that the cells could not have been synthesized exclusively from exogenous carbon dioxide or from respiratory carbon dioxide in equilibrium with the exogenous carbon dioxide. Kaneda & Roxburgh (1959) (Large, Peel & Quayle, 1962). On the basis of these data a scheme was proposed for a heterotrophic type of metabolism in which hydroxymethylation of glycine to give serine serves as a major pathway for synthesis of 3-C compounds from 2-C compounds.…”

Section: J R Quaylementioning

confidence: 99%

The Assimilation of 1-C compounds

Quayle¹

1963

Journal of General Microbiology

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Section: J R Quaylementioning

confidence: 99%

The Assimilation of 1-C compounds

Quayle¹

1963

Journal of General Microbiology

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“…A key point has been to understand how the bacterium incorporates C1 units into cell material. The serine cycle was elucidated in this organism during the early 1960s by Quayle and coworkers (6)(7)(8)(9). The assimilation of C1 units by this pathway requires continuous regeneration of glyoxylate from acetyl-CoA and can be achieved, in principle, via the well-known glyoxylate cycle (10).…”

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confidence: 99%

Demonstration of the ethylmalonyl-CoA pathway by using ¹³ C metabolomics

Peyraud

Kiefer

Christen

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

215

242

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The assimilation of one-carbon (C1) compounds, such as methanol, by serine cycle methylotrophs requires the continuous regeneration of glyoxylate. Instead of the glyoxylate cycle, this process is achieved by a not yet established pathway where CoA thioesters are known to play a key role. We applied state-of-the-art metabolomics and 13 C metabolomics strategies to demonstrate how glyoxylate is generated during methylotrophic growth in the isocitrate lyase-negative methylotroph Methylobacterium extorquens AM1. High-resolution mass spectrometry showed the presence of CoA thioesters specific to the recently proposed ethylmalonyl-CoA pathway. The operation of this pathway was demonstrated by short-term 13 C-labeling experiments, which allowed determination of the sequence of reactions from the order of label incorporation into the different CoA derivatives. Analysis of 13 C positional enrichment in glycine by NMR was consistent with the predicted labeling pattern as a result of the operation of the ethylmalonyl-CoA pathway and the unique operation of the latter for glyoxylate generation during growth on methanol. The results also revealed that 2 molecules of glyoxylate were regenerated in this process. This work provides a complete pathway for methanol assimilation in the model methylotroph M. extorquens AM1 and represents an important step toward the determination of the overall topology of its metabolic network. The operation of the ethylmalonyl-CoA pathway in M. extorquens AM1 has major implications for the physiology of these methylotrophs and their role in nature, and it also provides a common ground for C1 and C2 compound assimilation in isocitrate lyase-negative bacteria.13 C labeling ͉ CoA ester ͉ methylotroph ͉ one-carbon metabolism ͉ glyoxylate regeneration M ethylotrophic bacteria are organisms capable of using reduced carbon compounds, such as methanol or methane, as sole sources of carbon and energy, and they play a key role in carbon cycling in their environment. They also represent promising organisms in biotechnology for the conversion of one-carbon (C1) substrates to value-added products (1). The elucidation of the mechanisms enabling growth on reduced C1 compounds of Methylobacterium extorquens AM1, one of the most studied methylotrophs, has been a longstanding goal, and although great progress has been made (2-5), it is still not fully achieved. A key point has been to understand how the bacterium incorporates C1 units into cell material. The serine cycle was elucidated in this organism during the early 1960s by Quayle and coworkers (6-9). The assimilation of C1 units by this pathway requires continuous regeneration of glyoxylate from acetyl-CoA and can be achieved, in principle, via the well-known glyoxylate cycle (10). However, Dunstan and coworkers (11)(12)(13)(14) showed in 1972 and 1973 that M. extorquens AM1 lacks the key enzyme of the glyoxylate cycle, isocitrate lyase, but has an alternative route involving oxidation of acetate to glyoxylate that functions during growth on both C1 and C2 co...

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“…This indicates that a carboxylation reaction involving the conversion of a C3 acid into a C4 acid is present in the organism. A scheme was proposed (Large et al 1962) in which the conversion of C3 into C4 units is a key step in the carbon-assimilation pathway. This paper reports an investigation into the nature of the enzyme(s) involved in the carboxylation reaction, and the enzyme responsible appears to be phosphoenolpyruvate carboxylase [orthophosphate-oxaloacetate carboxylyase (phosphorylating), EC 4.1.1.31].…”

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confidence: 99%