Fig. 5: Organization of CIII2CIV cofactors and redox partners.
a The cofactors are shown inside the transparent map SC-2A of CIII2CIV with the same subunit colors as in Fig. 2: hemes bL and bH (periwinkle), heme c1 (green), hemes cp1 and cp2 (light blue), heme co (dark green), hemes b and b3 (purple). The [2Fe-2S] clusters are shown as yellow–red spheres. In all cases, the distances (heme-Fe to heme-Fe) between the heme cofactors are indicated. The positions of docked cyt c2 and cyt domain of cy are indicated as orange (heme c2) and red (heme cy) spheres, respectively, representing their heme-Fe atoms. All heme-Fe atoms corresponding to the top 50 docking positions for cyt c2 on CIV are shown as solid (<25 Å) or transparent (>25 Å) spheres, depending on their distances to heme cp2. In the case of CIII2, only the docking positions of cyt c2 and cyt cy on monomer A and between the monomers A and B are shown, omitting those located on monomer B. The TMH of cyt cy is shown in red at CIII2CIV interface. b The heme-Fe atoms of all 50 cyt c2 models docked onto CIV are plotted as function of their distances from heme cp1 and heme cp2, with the Fe atoms within 25 Å shown as solid spheres and those beyond 25 Å as transparent spheres. The vast majority of heme-Fe atoms of docked cyt c2 models are closer to heme cp2 than heme cp1 of CIV. c Top view of the map shown in a is presented to better visualize the distribution of the docked cyt domain of cy on monomer A and between the monomers A and B. In all cases, the heme-Fe atoms are depicted by spheres and colored as indicated above and on the figure.
