Recapitulation in Saccharomyces cerevisiae of cytochrome b mutations conferring resistance to atovaquone in Pneumocystis jiroveci.
نویسندگان
چکیده
Pneumocystis jiroveci (human-derived P. carinii) is an opportunistic pathogenic fungus which causes pneumonia and is life-threatening in immunocompromised individuals. Spontaneously acquired resistance to atovaquone, a hydroxynaphthoquinone that is used to treat P. jiroveci infections, was linked to mutations in the mitochondrially encoded cytochrome b gene. Because P. jiroveci cannot be easily cultivated, we have developed Saccharomyces cerevisiae as an alternative system to study atovaquone resistance mutations. In this work, we introduced seven mutations linked with atovaquone resistance in P. jiroveci into the S. cerevisiae cytochrome b gene. The effects of the mutations on the respiratory function and on the sensitivity to the inhibitor were then characterized. Six of the reported mutations lowered the sensitivity of the S. cerevisiae bc(1) complex to atovaquone, while one mutation had no effect on the drug resistance. These results were confirmed by monitoring the in vivo resistance of S. cerevisiae mutants which carried both the cytochrome b mutations and a deletion of the ABC transporter genes, allowing the drug to bypass the weakened efflux pump system. S. cerevisiae thus provides an easy-to-use system to characterize in vivo and in vitro cytochrome b mutations reported in pathogens and to assess their role in drug resistance.
منابع مشابه
Molecular basis for atovaquone resistance in Pneumocystis jirovecii modeled in the cytochrome bc(1) complex of Saccharomyces cerevisiae.
Atovaquone is a substituted hydroxynaphthoquinone that is widely used to prevent and clear Plasmodium falciparum malaria and Pneumocystis jirovecii pneumonia. Atovaquone inhibits respiration in target organisms by specifically binding to the ubiquinol oxidation site at center P of the cytochrome bc(1) complex. The failure of atovaquone treatment and mortality of patients with malaria and P. jir...
متن کاملMolecular basis of Toxoplasma gondii atovaquone resistance modeled in Saccharomyces cerevisiae.
0 d ondii is a widespread disease affecting primarily immunocomromised and pregnant individuals [1]. Atovaquone is a recently ntroduced anti-malarial compound with broad spectrum activty against various apicomplexan parasites [2–5] including T. ondii [6]. Approved by the FDA in 1995, this drug is a potent nd specific inhibitor of the cytochrome bc1 complex [7], an ssential respiratory enzyme pr...
متن کاملCytochrome b mutations that modify the ubiquinol-binding pocket of the cytochrome bc1 complex and confer anti-malarial drug resistance in Saccharomyces cerevisiae.
Atovaquone is a new anti-malarial agent that specifically targets the cytochrome bc1 complex and inhibits parasite respiration. A growing number of failures of this drug in the treatment of malaria have been genetically linked to point mutations in the mitochondrial cytochrome b gene. To better understand the molecular basis of atovaquone resistance in malaria, we introduced five of these mutat...
متن کاملPneumocystis jiroveci dihydropteroate synthase polymorphisms confer resistance to sulfadoxine and sulfanilamide in Saccharomyces cerevisiae.
Failure of anti-Pneumocystis jiroveci prophylaxis with sulfa drugs is associated with mutations within the putative active site of the fungal dihydropteroate synthase (DHPS), an enzyme encoded by the multidomain FAS gene. This enzyme is involved in the essential biosynthesis of folic acid. The most frequent polymorphisms are two mutations leading to two amino acid changes ((55)Trp-Arg-(57)Pro t...
متن کاملMolecular basis for atovaquone binding to the cytochrome bc1 complex.
Atovaquone is a substituted 2-hydroxynaphthoquinone that is used therapeutically to treat Plasmodium falciparum malaria, Pneumocystis carinii pneumonia, and Toxoplasma gondii toxoplasmosis. It is thought to act on these organisms by inhibiting the cytochrome bc1 complex. We have examined the interaction of atovaquone with the bc1 complex isolated from Saccharomyces cerevisiae, a surrogate, nonp...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- Antimicrobial agents and chemotherapy
دوره 47 9 شماره
صفحات -
تاریخ انتشار 2003