Ubiquinol, binding site modeling

Unlike the other ubiquinol binding sites presented above, the ubiquinol binding site in cytochrome bo% stabilizes a semiquinone during the oxidation of ubiquinol. A previous model placed the ubiquinone binding site of cytochrome bo within the extrinsic domain of subunit II, replacing the Cua site (Murray et al., 1999). However, several lines of evidence are available to refute this model. 

Fig. 8. Ubiquinol binding model in the Qp site. Ubiquinol was modeled based on the inhibitor-bound bc complex structures.

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