Fast electron transfer from cytochrome c6 and plastocyanin to photosystem I of Chlamydomonas reinhardtii requires PsaF.
To study the function of the PsaF subunit of photosystem I (PSI), the interactions between plastocyanin or cytochrome c6 and PSI isolated from wild-type and a PsaF-deficient mutant of Chlamydomonas reinhardtii have been examined using cross-linking techniques and flash absorption spectroscopy. We show that efficient electron transfer from both plastocyanin and cytochrome c6 to PSI depends on PsaF. A remarkable feature of the PSI complex of C. reinhardtii is that both plastocyanin and cytochrome c6 reduce P700+ with first-order kinetics and a half-time of 3 micros, which is unique among photosynthetic organisms examined.
Hippler
M
M
Department of Molecular Biology, University of Geneva, Switzerland.
Drepper
F
F
Farah
J
J
Rochaix
J D
JD
D000818:Animals; D016825:Chlamydomonas reinhardtii / Q000235:genetics / Q000378:metabolism*; D003432:Cross-Linking Reagents; D003580:Cytochromes / Q000378:metabolism*; D045348:Cytochromes f; D004579:Electron Transport; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D009154:Mutation; D010084:Oxidation-Reduction; D045322:Photosynthetic Reaction Center Complex Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D045331:Photosystem I Protein Complex; D010970:Plastocyanin / Q000378:metabolism*; D015800:Protozoan Proteins
D003432:Cross-Linking Reagents; D003580:Cytochromes; D008565:Membrane Proteins; D045322:Photosynthetic Reaction Center Complex Proteins; D045331:Photosystem I Protein Complex; D015800:Protozoan Proteins; C489801:psaF protein, Chlamydomonas reinhardtii; D010970:Plastocyanin; D045348:Cytochromes f