Abstract
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.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Chlamydomonas reinhardtii / genetics
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Chlamydomonas reinhardtii / metabolism*
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Cross-Linking Reagents
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Cytochromes / metabolism*
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Cytochromes f
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Electron Transport
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Membrane Proteins / genetics
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Membrane Proteins / metabolism
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Membrane Proteins / physiology*
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Mutation
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Oxidation-Reduction
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Photosynthetic Reaction Center Complex Proteins / genetics
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Photosynthetic Reaction Center Complex Proteins / isolation & purification
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Photosynthetic Reaction Center Complex Proteins / metabolism*
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Photosystem I Protein Complex*
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Plastocyanin / metabolism*
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Protozoan Proteins*
Substances
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Cross-Linking Reagents
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Cytochromes
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Membrane Proteins
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Photosynthetic Reaction Center Complex Proteins
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Photosystem I Protein Complex
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Protozoan Proteins
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psaF protein, Chlamydomonas reinhardtii
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Plastocyanin
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Cytochromes f