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Schlagwörter:
Cytochrome b6f complex; Cytochrome bc1 complex; Electron crystallography; Stigmatellin; Membrane protein; Chlamydomonas reinhardtii
Zusammenfassung:
Electron crystallography of the chloroplastic b6f complex allowed the calculation of projection maps of crystals negatively stained or embedded in glucose. This gives insights into the overall structure of the extra- and transmembrane domains of the complex. A comparison with the structure of the bc1 complex, the mitochondrial homologue of the b6f complex, suggests that the transmembrane domains of the two complexes are very similar, confirming the structural homology deduced from sequence analysis. On the other hand, the extramembrane organisation of the c-type cytochrome and of the Rieske protein seems quite different. Nevertheless, the same type of movement of the Rieske protein is observed in the b6f as in the bc1 complex upon the binding of the quinol analogue stigmatellin. Crystallographic data also suggest movements in the transmembrane domains of the b6f complex, which would be specific of the b6f complex.
