Reconstructing the Qo site of Plasmodium falciparum bc 1 complex in the yeast enzyme

PLoS One. 2013 Aug 12;8(8):e71726. doi: 10.1371/journal.pone.0071726. eCollection 2013.

Abstract

The bc 1 complex of the mitochondrial respiratory chain is essential for Plasmodium falciparum proliferation, the causative agent of human malaria. Therefore, this enzyme is an attractive target for antimalarials. However, biochemical investigations of the parasite enzyme needed for the study of new drugs are challenging. In order to facilitate the study of new compounds targeting the enzyme, we are modifying the inhibitor binding sites of the yeast Saccharomyces cerevisiae to generate a complex that mimics the P. falciparum enzyme. In this study we focused on its Qo pocket, the site of atovaquone binding which is a leading antimalarial drug used in treatment and causal prophylaxis. We constructed and studied a series of mutants with modified Qo sites where yeast residues have been replaced by P. falciparum equivalents, or, for comparison, by human equivalents. Mitochondria were prepared from the yeast Plasmodium-like and human-like Qo mutants. We measured the bc 1 complex sensitivity to atovaquone, azoxystrobin, a Qo site targeting fungicide active against P. falciparum and RCQ06, a quinolone-derivative inhibitor of P. falciparum bc 1 complex.The data obtained highlighted variations in the Qo site that could explain the differences in inhibitor sensitivity between yeast, plasmodial and human enzymes. We showed that the yeast Plasmodium-like Qo mutants could be useful and easy-to-use tools for the study of that class of antimalarials.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Antimalarials / chemistry*
  • Antimalarials / metabolism
  • Antimalarials / pharmacology
  • Atovaquone / chemistry*
  • Atovaquone / metabolism
  • Atovaquone / pharmacology
  • Binding Sites* / genetics
  • Drug Resistance / genetics
  • Electron Transport Chain Complex Proteins / antagonists & inhibitors
  • Electron Transport Chain Complex Proteins / chemistry*
  • Electron Transport Chain Complex Proteins / metabolism
  • Enzyme Activation / drug effects
  • Humans
  • Inhibitory Concentration 50
  • Models, Molecular
  • Molecular Conformation
  • Molecular Sequence Data
  • Mutation
  • Plasmodium falciparum / drug effects
  • Plasmodium falciparum / enzymology*
  • Plasmodium falciparum / genetics
  • Protein Binding
  • Sequence Alignment
  • Yeasts / drug effects
  • Yeasts / enzymology

Substances

  • Antimalarials
  • Electron Transport Chain Complex Proteins
  • Atovaquone

Grants and funding

The work was supported by a Centre National de la Recherche Scientifique (CNRS) studentship to CV and CNRS recurrent funding to BM. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.