Cytochrome bc1 complex (Plasmodium species) (Cyt bc1)

The cytochrome bc1 complex (complex III) of Plasmodium species is a multi-subunit mitochondrial enzyme pivotal for energy metabolism, coupling the transfer of electrons from ubiquinol to cytochrome c with vectorial proton translocation across the mitochondrial inner membrane[5][2]. Its catalytic core consists of cytochrome b, cytochrome c1, and the Rieske iron-sulfur protein subunits, each containing essential redox cofactors[5]. Antimalarial drugs such as atovaquone and novel compounds selectively target the Qo or Qi sites, blocking electron flow and causing parasite death without directly targeting host cells when selectivity is achieved[5][1][2][3][4]. Resistance mutations in cytochrome b are a major therapeutic challenge, as they alter drug binding and necessitate novel inhibitor design[5][2][3]. The structural and functional conservation (and divergence from the human complex) allows rational design of more selective, potent, and safer antimalarial drugs[2][5][1][4][3].

Other names

Complex IIImitochondrial complex IIIubiquinol–cytochrome c oxidoreductaserespiratory chain complex IIIcyt bc1

Competitive or non-competitive inhibition at the Qo or Qi binding sites, blocking electron transfer from ubiquinol to cytochrome c1 Disruption of the mitochondrial electron transport chain, leading to loss of ATP production and parasite death