Cytochrome bc1 complex subunit QcrB (QcrB)

QcrB is the cytochrome b subunit of the cytochrome bc1 complex (also known as Complex III), a critical component of the respiratory electron transport chain in both prokaryotes and eukaryotes. This complex is essential for ATP synthesis, facilitating electron transfer from ubiquinol or menaquinol to cytochrome c, and coupling this process to proton translocation across membranes. The Qi site on cytochrome b (part of QcrB) has been identified as a promiscuous drug target in various pathogens including Trypanosoma cruzi, Leishmania donovani, and Mycobacterium tuberculosis. Resistance mutations have been mapped directly onto residues within or near these binding sites on QcrB.

Other names

Cytochrome bComplex III subunit QcrB

Inhibition of ubiquinol/menaquinol oxidation and cytochrome c reduction by binding to the Qi site, competing with menaquinone binding, or blocking quinone access/binding.