Figure 1.

The dimeric cytochrome b₆f complex (PDB ID 4H44). Prosthetic groups in the cytochrome b₆f complex. Hemes b_p (red), b_n (red) and c_n (black) are redox-active prosthetic groups located within the trans-membrane domain, and constitute the low-potential chain. Heme f (black) and [2Fe-2S] cluster (orange/yellow spheres) form the high-potential chain, and are associated with the p-side extrinsic domains of cytochrome f and ISP, respectively. A chlorophyll-a (green) and a β-carotene (yellow) are also associated with the complex. Polypeptides are shown as ribbons. Color code: cytochrome b₆ (cyt b₆), wheat; subunit IV (subIV), orange; cytochrome f (cyt f), cyan; iron-sulfur protein (ISP), yellow; PetL, red; PetM, green; PetG, blue; PetN, gray.