Direct evidence for the atovaquone action on the Plasmodium cytochrome bc1 complex. Issue 3 (June 2015)

• Record Type: Journal Article
• Authors: Siregar, Josephine E.; Kurisu, Genji; Kobayashi, Tamaki; Matsuzaki, Motomichi; Sakamoto, Kimitoshi; Mi-ichi, Fumika; Watanabe, Yoh-ichi; Hirai, Makoto; Matsuoka, Hiroyuki; Syafruddin, Din; Marzuki, Sangkot; Kita, Kiyoshi
• Is Part Of: Parasitology international. Volume 64:Issue 3(2015:Jun.)
• Page Start: 295
• Page End: 300
• Publication Date: 2015-06
• Subjects: Parasitology -- Periodicals; Parasites -- Periodicals; Parasitic Diseases -- Periodicals; Parasitology -- Periodicals; Parasitologie -- Périodiques; 571.99905
• DOI: 10.1016/j.parint.2014.09.011
• Languages: English
• ISSNs: 1383-5769

Abstract

<abstract abstract-type="author" id="ab0005"> <title id="st0005">Abstract</title> <sec> <p id="sp0005">Atovaquone, a coenzyme Q analogue has been indicated to specifically target the cytochrome <italic>bc</italic><sub>1</sub> complex of the mitochondrial respiratory chain in the malarial parasite and other protozoan. Various mutations in the quinone binding site of the cytochrome <italic>b</italic> gene of <italic>Plasmodium</italic> spp. such as M133I, L144S, L271V, K272R, Y268C, Y268S, Y268N, and V284F are suggesting to associate with resistance to atovaquone. There is no direct evidence of relation between the mutations and resistance to atovaquone in <italic>Plasmodium</italic> parasite that has been available. Technical difficulties in isolating active assayable mitochondria in the malarial parasite hinder us to obtain direct biochemical evidence to support the relation between the mutations and drug resistance.</p> <p id="sp0010">The establishment of a mitochondrial isolation method for the malaria parasite has allowed us to test the degree of resistance of <italic>Plasmodium berghei</italic> isolates to atovaquone directly. We have tested the activity of dihydroorotate (DHO)-cytochrome <italic>c</italic> reductase in various <italic>P. berghei</italic> atovaquone resistant clones in the presence of a wide concentration range of atovaquone. Our results show the IC<sub>50</sub> of <italic>P. berghei</italic> atovaquone resistant clones is much higher (1.5 up to 40 nM) in comparison to the atovaquone sensitive clones (0.132–0.465 nM). The highest IC<sub>50</sub> was revealed in clones carrying Y268C and Y268N mutations (which play an important role in atovaquone resistance in <italic>Plasmodium falciparum</italic>), with an approximately 100-fold increase. The findings indicate the importance of the mutation in the quinone binding site of the cytochrome <italic>b</italic> gene and that provide a direct evidence for the atovaquone inhibitory mechanism in the cytochrome <italic>bc</italic><sub>1</sub> complex of the parasite.</p> </sec> </abstract>