FIGURE 1. Structural model of the Qi-site in R. sphaeroides.
The structure from the bovine mitochondrial bc1 complex (Protein Data Bank code 1pp9) is shown, mutated in silico, and renumbered to conform to the R. sphaeroides sequence. Groups discussed in the text are shown as ball and stick models. The distances shown are in Å and represent the H-bond length between donor and acceptor atoms. Heme bH is colored yellow. Other critical residues involved as putative ligands to the quinone species at the site shown in CPK colors, and labeled by residue number. (Stereo pair for crossed-eye viewing.)
