Protozoan mitochondrial respiratory chain

The protozoan mitochondrial respiratory chain refers to a multi-protein enzyme system located in the inner membrane of mitochondria in protozoan parasites. It consists primarily of four large complexes (I–IV) and associated molecules (such as ubiquinone and cytochrome c) that mediate the transfer of electrons from metabolic substrates to molecular oxygen, a process coupled with the pumping of protons across the membrane to generate a proton motive force. This electrochemical gradient is harnessed by ATP synthase to drive ATP synthesis, forming the basis of oxidative phosphorylation and energy metabolism in eukaryotic cells. In protozoan parasites from groups such as Apicomplexa, unique adaptations in the composition and structure of these complexes provide potential therapeutic targets that differ from their mammalian counterparts. Inhibitors targeting the protozoan mitochondrial electron transport chain, such as atovaquone against Plasmodium and Toxoplasma, have demonstrated antiparasitic efficacy by blocking electron transfer, collapsing the proton gradient, and inhibiting ATP generation, ultimately resulting in parasite death. Selectivity and safety remain a concern due to similarities with the mammalian mitochondrial respiratory chain.

Other names

Protozoan mitochondrial electron transport chainProtozoan oxidative phosphorylation chainProtozoan mETC

Inhibition of electron transport chain complexes (e.g., complex III inhibition by atovaquone); Disruption of proton gradient and ATP production