Phosphoenolpyruvate carboxylase dentified as a key enzyme in erythrocytic Plasmodium falciparum carbon metabolism

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 > Institute of Cardiovascular and Medical Sciences
College of Medical Veterinary and Life Sciences > Institute of Infection Immunity and Inflammation
College of Medical Veterinary and Life Sciences > Institute of Molecular Cell and Systems Biology
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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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
371796The Wellcome Centre for Molecular Parasitology ( Core Support )Andrew WatersWellcome Trust (WELLCOME)085349/Z/08/ZIII - PARASITOLOGY
371798The Wellcome Centre for Molecular Parasitology ( Core Support )Andrew WatersWellcome Trust (WELLCOME)085349/B/08/ZIII - PARASITOLOGY