The model contains six of the eight predicted transmembrane helices (A-F) and putative amphipathic helices at the N-terminal end (a), between helices A and B (ab), and between helices C and D (cd).
Residues shown in blue are those which when mutated give rise to effects (inhibitor resistance, modified kinetics, change in semiquinone stability) at the Qi-site.
Residues shown in orange or yellow are those which when mutated give rise to inhibitor resistance or modified kinetics at the Qo-site.
Ubiquinones are shown to indicate the approximate location of the Qo-site (purple) and the Qi-site (green). The picture was decorated with text using Paint. The coordinates for the model were generated using the Ribosome function from the PSAAM package.
Cytochrome b viewed from the cytoplasmic side.
Cytochrome b - side view.
Model of Qo-site.
The side chains of residues around the Qo-site are shown, with positions of predicted helices painted in as transparent cylinders. The residues are depicted in the ball-and-stick representation obtained using the Togl Side Chains On, Togl Backbone off, Highlight residues by number, Circle atoms, and Number residues functions of PDVWIN.
Model of Qi-site.
The side chains of residues around the Qi-site are shown, with positions of predicted helices painted in as transparent cylinders.