Interaction of a phenolic inhibitor with photosystem II particles.
Photosystem II particles have been prepared from spinach and Chlamydomonas reinhardii CW 15 thylakoids. Photosynthetic electron transport in these particles is inhibited by phenolic compounds like dinoseb, but not by atrazine and diuron. The labeling patterns obtained by photoaffinity labels derived from either atrazine (azido-atrazine) or the phenolic herbicide dinoseb (azido-dinoseb) were compared in photosystem II particles and thylakoids. Whereas azido-atrazine in thylakoids of spinach as well as of Chlamydomonas labels a 32-kilodalton peptide, this label does not react in photosystem II particle preparations. Azido-dinoseb, however, labels both the thylakoid membranes and the particles, predominantly polypeptides in the 40-53 kilodalton molecular weight region. Since the latter polypeptides are probably part of the reaction center of photosystem II, it is suggested that phenolic compounds have their inhibition site within the reaction center complex. This indicates that the atrazine-binding 32-kilodalton peptide is either absent or functionally inactive in photosystem II particles, whereas the phenol inhibitor-binding peptides are not.
Johanningmeier
U
U
Department of Biology, Ruhr University, D-4630 Bochum 1, FRG.
Neumann
E
E
Oettmeier
W
W
D019297:2,4-Dinitrophenol / Q000031:analogs & derivatives / Q000494:pharmacology; D000345:Affinity Labels; D020418:Algal Proteins / Q000378:metabolism; D000818:Animals; D001280:Atrazine / Q000031:analogs & derivatives / Q000494:pharmacology; D016825:Chlamydomonas reinhardtii / Q000378:metabolism; D004579:Electron Transport / Q000187:drug effects; D010636:Phenols / Q000494:pharmacology*; D045332:Photosystem II Protein Complex / Q000737:chemistry / Q000187:drug effects* / Q000378:metabolism; D010940:Plant Proteins / Q000378:metabolism; D015800:Protozoan Proteins / Q000378:metabolism; D018724:Spinacia oleracea / Q000378:metabolism; D020524:Thylakoids / Q000187:drug effects / Q000378:metabolism
D000345:Affinity Labels; D020418:Algal Proteins; D010636:Phenols; D045332:Photosystem II Protein Complex; D010940:Plant Proteins; D015800:Protozoan Proteins; D019297:2,4-Dinitrophenol; D001280:Atrazine; C018527:dinoseb