InterPro domain: IPR002325

The cytochrome b6f integral membrane protein complex transfers electrons between the two reaction centre complexes of oxygenic photosynthetic membranes, and participates in formation of the transmembrane electrochemical proton gradient by also transferring protons from the stromal to the internal lumen compartment. The cytochrome b6f complex contains four polypeptides: cytochrome f (285 aa); cytochrome b6 (215 aa); Rieske iron-sulphur protein (179 aa); and subunit IV (160 aa) [ 1 ]. In its structure and functions, the cytochrome b6f complex bears extensive analogyto the cytochrome bc1 complex of mitochondria and photosynthetic purple bacteria; cytochrome f (cyt f) plays a role analogous to that of cytochromec1, in spite of their different structures [ 2 ].

1. Structural aspects of the cytochrome b6f complex; structure of the lumen-side domain of cytochrome f. J. Bioenerg. Biomembr. 26, 31-47
2. Cytochrome f revealed. Trends Biochem. Sci. 20, 217-8