Fig. 5
QrcCD homology-based model. a The structural model of Qrc subunits C (QrcC, purple with transparency) and D (QrcD, light purple) is superimposed on the structure of subunits B C-terminus (ActB, beige with transparency) and C (ActC, orange) of the alternative complex III (PDB code: 6FOK29). A cartoon representation is used to depict the backbone structure of the two proteins and the iron–sulfur clusters are represented by sticks, with iron and sulfur atoms colored in orange and yellow, respectively. b The Qrc residues that are putatively involved in quinone binding and proton translocation are highlighted using sticks with carbons colored in pink and cyan, respectively. The approximate membrane boundaries are depicted in dashed lines
