{"title":"Shortening of life-time of the pair [P680+Pheo-] contributes to general inhibitory effect of dinoseb on electron transfer in PS-II.","authors":"K Vyacheslav, A Suleyman, Z Serguei","doi":"","DOIUrl":null,"url":null,"abstract":"<p><p>It is shown that dinoseb, added to subchloroplast photosystem-II (PS-II) preparations from pea at a concentration higher than 5 microM, along with blocking the electron transfer on the acceptor side of PS-II, induces the following effects revealing its capability to have redox interaction with the components of PS-II reaction center (RC)-pheophytin (Pheo) and chlorophyll P680: (1) acceleration of the dark relaxation of absorbance (delta A) and chlorophyll fluorescence (delta F) changes related to photoreduction of Pheo as a result of the photoreaction [P680Pheo] [symbol: see text] [P680Pheo-] that leads to elimination of the delta A and delta F at a concentration of the inhibitor higher than 50 microM; (2) lowering of the maximum level of fluorescence (F) due to a decrease of delta F under the condition when the electron acceptor, QA, is reduced; (3) loss of the described effects of dinoseb and appearance of its capability to donate electron to RC of PS-II in the presence of dithionite which reduces dinoseb in the dark; (4) inhibition of delta A related to photooxidation of P680; (5) activation of delta A related to photooxidation P700 in photosystem-I (PS-I) preparations (a similar effect is observed upon the addition of 0.2 mM methylviologen). It is suggested that redox interaction with the pair [P680+Pheo-] leading to the shortening of its life-time contributes to the general effect of inhibition of electron transfer in PS-II by dinoseb.</p>","PeriodicalId":13281,"journal":{"name":"Indian journal of biochemistry & biophysics","volume":"37 6","pages":"491-7"},"PeriodicalIF":1.5000,"publicationDate":"2000-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Indian journal of biochemistry & biophysics","FirstCategoryId":"99","ListUrlMain":"","RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"BIOCHEMISTRY & MOLECULAR BIOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
It is shown that dinoseb, added to subchloroplast photosystem-II (PS-II) preparations from pea at a concentration higher than 5 microM, along with blocking the electron transfer on the acceptor side of PS-II, induces the following effects revealing its capability to have redox interaction with the components of PS-II reaction center (RC)-pheophytin (Pheo) and chlorophyll P680: (1) acceleration of the dark relaxation of absorbance (delta A) and chlorophyll fluorescence (delta F) changes related to photoreduction of Pheo as a result of the photoreaction [P680Pheo] [symbol: see text] [P680Pheo-] that leads to elimination of the delta A and delta F at a concentration of the inhibitor higher than 50 microM; (2) lowering of the maximum level of fluorescence (F) due to a decrease of delta F under the condition when the electron acceptor, QA, is reduced; (3) loss of the described effects of dinoseb and appearance of its capability to donate electron to RC of PS-II in the presence of dithionite which reduces dinoseb in the dark; (4) inhibition of delta A related to photooxidation of P680; (5) activation of delta A related to photooxidation P700 in photosystem-I (PS-I) preparations (a similar effect is observed upon the addition of 0.2 mM methylviologen). It is suggested that redox interaction with the pair [P680+Pheo-] leading to the shortening of its life-time contributes to the general effect of inhibition of electron transfer in PS-II by dinoseb.
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Started in 1964, this journal publishes original research articles in the following areas: structure-function relationships of biomolecules; biomolecular recognition, protein-protein and protein-DNA interactions; gene-cloning, genetic engineering, genome analysis, gene targeting, gene expression, vectors, gene therapy; drug targeting, drug design; molecular basis of genetic diseases; conformational studies, computer simulation, novel DNA structures and their biological implications, protein folding; enzymes structure, catalytic mechanisms, regulation; membrane biochemistry, transport, ion channels, signal transduction, cell-cell communication, glycobiology; receptors, antigen-antibody binding, neurochemistry, ageing, apoptosis, cell cycle control; hormones, growth factors; oncogenes, host-virus interactions, viral assembly and structure; intermediary metabolism, molecular basis of disease processes, vitamins, coenzymes, carrier proteins, toxicology; plant and microbial biochemistry; surface forces, micelles and microemulsions, colloids, electrical phenomena, etc. in biological systems. Solicited peer reviewed articles on contemporary Themes and Methods in Biochemistry and Biophysics form an important feature of IJBB.
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