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ON THE NATURE OF THE INTERMEDIATE ELECTRON ACCEPTOR (A 1 ) IN THE PHOTOSYSTEM I REACTION CENTER
Author(s) -
Baltimore Barbara G.,
Malkin Richard
Publication year - 1980
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1980.tb03733.x
Subject(s) - p700 , photosynthetic reaction centre , electron acceptor , chemistry , photosystem i , photochemistry , electron donor , pheophytin , acceptor , electron paramagnetic resonance , electron transfer , light harvesting complexes of green plants , photosystem ii , nuclear magnetic resonance , photosynthesis , catalysis , physics , biochemistry , condensed matter physics
— A sodium dodecyl sulfate‐Photosystem I (PSI) complex has been prepared and characterized with respect to its electron acceptors. Component X and iron‐sulfur centers A and B are absent from this preparation but the intermediate electron acceptor (A 1 ) is present. Flash‐induced absorbance changes at 25°C show charge separation, followed by a back‐reaction with a half‐time of 5 µs. The spectrum of the flash‐induced change from 350 to 550 nm indicates a contribution from the intermediate electron acceptor, A 1 , as well as from P700 + . EPR studies show that A 1 is associated with a free‐radical signal having a g‐value of 2.0025 and a linewidth of 12 gauss. A, would appear to be associated with a monomeric form of either Chi α or pheophytin a.