Storm, J., Sethia, S., Blackburn, G. J., Chokkathukalam, A., Watson, D. G., Breitling, R. , Coombs, G. H. and Müller, S. (2014) Phosphoenolpyruvate carboxylase dentified as a key enzyme in erythrocytic Plasmodium falciparum carbon metabolism. PLoS Pathogens, 10(1), e1003876. (doi: 10.1371/journal.ppat.1003876) (PMID:24453970) (PMCID:PMC3894211)
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Abstract
Phospoenolpyruvate carboxylase (PEPC) is absent from humans but encoded in thePlasmodium falciparum genome, suggesting that PEPC has a parasite-specific function. To investigate its importance in P. falciparum, we generated a pepc null mutant (D10Δpepc), which was only achievable when malate, a reduction product of oxaloacetate, was added to the growth medium. D10Δpepc had a severe growth defect in vitro, which was partially reversed by addition of malate or fumarate, suggesting that pepc may be essential in vivo. Targeted metabolomics using 13C-U-D-glucose and 13C-bicarbonate showed that the conversion of glycolytically-derived PEP into malate, fumarate, aspartate and citrate was abolished in D10Δpepc and that pentose phosphate pathway metabolites and glycerol 3-phosphate were present at increased levels. In contrast, metabolism of the carbon skeleton of 13C,15N-U-glutamine was similar in both parasite lines, although the flux was lower in D10Δpepc; it also confirmed the operation of a complete forward TCA cycle in the wild type parasite. Overall, these data confirm the CO2 fixing activity of PEPC and suggest that it provides metabolites essential for TCA cycle anaplerosis and the maintenance of cytosolic and mitochondrial redox balance. Moreover, these findings imply that PEPC may be an exploitable target for future drug discovery.
| Item Type: | Articles |
|---|---|
| Status: | Published |
| Refereed: | Yes |
| Glasgow Author(s) Enlighten ID: | Muller, Professor Sylke and Chokkathukalam, Dr Achuthanunni and Storm, Dr Janet and Breitling, Professor Rainer and Coombs, Professor Graham |
| Authors: | Storm, J., Sethia, S., Blackburn, G. J., Chokkathukalam, A., Watson, D. G., Breitling, R., Coombs, G. H., and Müller, S. |
| College/School: | College of Medical Veterinary and Life Sciences > School of Cardiovascular & Metabolic Health College of Medical Veterinary and Life Sciences > School of Infection & Immunity College of Medical Veterinary and Life Sciences > School of Molecular Biosciences |
| Journal Name: | PLoS Pathogens |
| Publisher: | Public Library of Science |
| ISSN: | 1553-7366 |
| ISSN (Online): | 1553-7374 |
| Copyright Holders: | Copyright © 2014 The Authors |
| First Published: | First published in PLoS Pathogens 10(1):e1003876 |
| Publisher Policy: | Reproduced under a Creative Commons License |
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