Coccidian mitochondrial energy metabolism pathway

The mitochondrial energy metabolism pathway in Coccidia (and other Apicomplexa) is a critical system for parasite survival, serving as a primary target for several classes of antiprotozoal drugs (Vaidya & Mather, 2009). Unlike mammalian mitochondria, the coccidian respiratory chain is essential not only for ATP production through oxidative phosphorylation but also for providing the electron sink required for de novo pyrimidine biosynthesis via the enzyme dihydroorotate dehydrogenase (DHODH) (Goodman et al., 2007). This pathway includes the mitochondrial electron transport chain (mETC), where the cytochrome bc1 complex (Complex III) is a particularly vulnerable site. Drugs such as atovaquone and decoquinate bind to the ubiquinol oxidation site (Qo site) of the cytochrome bc1 complex, effectively halting electron flow (Fry & Williams, 1984). This inhibition leads to a collapse of the mitochondrial membrane potential, resulting in the death of the parasite. Because of the structural differences between parasite and host mitochondrial complexes, these pathways offer a high degree of therapeutic selectivity, although the rapid emergence of drug resistance remains a significant challenge in veterinary and human medicine (Mather et al., 2010).

Other names

Apicomplexan mitochondrial electron transport chainCoccidian respiratory chainEimeria mitochondrial pathwayMitochondrial energy metabolism in Apicomplexa

Inhibition of the cytochrome bc1 complex (Complex III) within the electron transport chain, disruption of the mitochondrial membrane potential, and indirect inhibition of de novo pyrimidine biosynthesis.