Figure 6. Electron density at the Qi site in native chicken crystals. The refined model of the complex, superimposed on a 2Fo-Fc map, where Fc and Fc are calculated from the refined model with ubiquinone omitted to avoid phase bias, contoured at 1.1 s. The superimposed model is the refined structure of the complex, including ubiquinone with its headgroup in the center of the figure. Panels A and B show two different views related by approximately 90° rotation about a vertical axis.