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Interaction of the Quinone Analogue, DBMIB, with the Photosynthetic Rieske Iron‐Sulfur Center
Author(s) -
Malkin Richard
Publication year - 1981
Publication title -
israel journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 54
eISSN - 1869-5868
pISSN - 0021-2148
DOI - 10.1002/ijch.198100055
Subject(s) - plastoquinone , chemistry , photosynthetic reaction centre , electron paramagnetic resonance , photosynthesis , photochemistry , chloroplast , electron transfer , nuclear magnetic resonance , thylakoid , biochemistry , physics , gene
Addition of the plastoquinone analogue, DBMIB, to chloroplasts results in the appearance of an EPR signal at g = 1.94 which is observed at cryogenic temperatures. Studies with subchloroplast fragments which either contain or lack the Rieske iron‐sulfur center indicate the presence of this electron carrier is required for the DBMIB‐induced EPR signal. A correlation between the disappearance of the Rieske center signal at g = 1.89 and the appearance of the DBMIB‐induced signal at g = 1.94 suggests DBMIB alters the Rieske center to produce the new signal. Similar effects were observed in photosynthetic membrane fragments from a blue‐green alga and a photosynthetic bacterium. It has been possible to use the DBMIB‐induced signal to test for interaction of other inhibitors in the region of the Rieske center. These results are considered in terms of models in which quinone and the Rieske center function as a donor‐acceptor pair during physiological electron transport.