Plasmodium falciparum mitochondrial cytochrome bc1 complex

The Plasmodium falciparum mitochondrial cytochrome bc1 complex (Complex III) is a multisubunit enzyme involved in the parasite's mitochondrial respiratory chain. It catalyzes the transfer of electrons from ubiquinol to cytochrome c, coupling this to the translocation of protons across the inner mitochondrial membrane. This process is fundamental for maintaining the mitochondrial membrane potential and for energy production (ATP synthesis). In Plasmodium falciparum, cytochrome bc1 is also crucial for regenerating ubiquinone, which is required for dihydroorotate dehydrogenase activity and, therefore, for pyrimidine biosynthesis. The complex is a validated target for antimalarial drugs such as atovaquone; inhibitors of bc1 disrupt the parasite's energy metabolism and have lethal effects. However, mutations in the cytochrome b subunit can confer resistance to these inhibitors, posing challenges for treatment and drug development[1][2][3][5].

Other names

Cytochrome bc1 complexComplex IIIubiquinol-cytochrome c oxidoreductaserespiratory Complex IIIcyt bc1

Inhibition of electron transfer from ubiquinol to cytochrome c - Disruption/collapse of mitochondrial membrane potential - Inhibition of de novo pyrimidine biosynthesis (by halting oxidative recycling of ubiquinone, thereby blocking dihydroorotate dehydrogenase)