Saccharomyces cerevisiae-based mutational analysis of the bc1 complex Qo site residue 279 to study the trade-off between atovaquone resistance and function.
The bc1 complex is central to mitochondrial bioenergetics and the target of the antimalarial drug atovaquone that binds in the quinol oxidation (Qo) site of the complex. Structural analysis has shown that the Qo site residue Y279 (Y268 in Plasmodium falciparum) is key for atovaquone binding. Consequently, atovaquone resistance can be acquired by mutation of that residue. In addition to the probability of amino acid substitution, the level of atovaquone resistance and the loss of bc1 complex activity that are associated with the novel amino acid would restrict the nature of resistance-driven mutations occurring on atovaquone exposure in native parasite populations. Using the yeast model, we characterized the effect of all the amino acid replacements resulting from a single nucleotide substitution at codon 279: Y279C, Y279D, Y279F, Y279H, Y279N, and Y279S (Y279C, D, F, H, N, and S). Two residue changes that required a double nucleotide substitution, Y279A and W, were added to the series. We found that mutations Y279A, C, and S conferred high atovaquone resistance but decreased the catalytic activity. Y279F had wild-type enzymatic activity and sensitivity to atovaquone, while the other substitutions caused a dramatic respiratory defect. The results obtained with the yeast model were examined in regard to atomic structure and compared to the reported data on the evolution of acquired atovaquone resistance in P. falciparum.
Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Gif-sur-Yvette, France.
Zehua
Z
Song
UMR 216, Faculté de Pharmacie de Paris, Université Paris Descartes, Paris, France UMR 216, Institut de Recherche pour le Développement, Paris, France.
Jérôme
J
Clain
Institut de Chimie des Substances Naturelles, CNRS, UPR 2301, Labex LERMIT, Gif-sur-Yvette, France.
Bogdan I
BI
Iorga
Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Gif-sur-Yvette, France.
Zhou
Z
Yi
Plant Research Laboratory, Michigan State University, East Lansing, Michigan, USA.
Nicholas
N
Fisher
Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Gif-sur-Yvette, France meunier@cgm.cnrs-gif.fr.
Brigitte
B
Meunier
D019943:Amino Acid Substitution; D000962:Antimalarials / Q000494:pharmacology*; D053626:Atovaquone / Q000494:pharmacology*; D005075:Biological Evolution; D002384:Catalysis; D003062:Codon / Q000235:genetics; D004252:DNA Mutational Analysis; D004351:Drug Resistance / Q000235:genetics; D014450:Electron Transport Complex III / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D006873:Hydroquinones / Q000737:chemistry*; D008024:Ligands; D008958:Models, Molecular; D009154:Mutation; D010084:Oxidation-Reduction; D010963:Plasmodium falciparum / Q000187:drug effects / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000235:genetics*
D000962:Antimalarials; D003062:Codon; D006873:Hydroquinones; D008024:Ligands; D014450:Electron Transport Complex III; D053626:Atovaquone