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Title

Molecular and Biophysical Analysis of Herbicide-Resistant Mutants of Chlamydomonas reinhardtii: Structure-Function Relationship of the Photosystem II D1 Polypeptide

Authors
Pfister, Klaus
Togasaki, Robert K.
Mets, Laurens
Published in Plant Cell. 1989, vol. 1, no. 3, p. 361-371
Abstract Plants and green algae can develop resistance to herbicides that block photosynthesis by competing with quinones in binding to the chloroplast photosystem II (PSII) D1 polypeptide. Because numerous herbicide-resistant mutants of Chlamydomonas reinhardtii with different patterns of resistance to such herbicides are readily isolated, this system provides a powerful tool for examining the interactions of herbicides and endogenous quinones with the photosynthetic membrane, and for studying the structure-function relationship of the D1 protein with respect to PSII electron transfer. Here we report the results of DNA sequence analysis of the D1 gene from four mutants not previously characterized at the molecular level, the correlation of changes in specific amino acid residues of the D1 protein with levels of resistance to the herbicides atrizine, diuron, and bromacil, and the kinetics of fluorescence decay for each mutant, which show that changes at two different amino acid residues dramatically slow PSII electron transfer. Our analyses, which identify a region of 57 amino acids of the D1 polypeptide involved in herbicide binding and which define a D1 binding niche for the second quinone acceptor, QB of PSII, provide a strong basis of support for structural and functional models of the PSII reaction center.
Keywords Amino Acid SequenceAnimalsBase SequenceBinding SitesChlamydomonas reinhardtii/drug effects/geneticsMolecular cloningDNADrug Resistance/geneticsFluorometryHerbicides/pharmacologyKineticsMolecular Sequence DataMutationPhotosynthetic Reaction Center Complex Proteins/chemistry/geneticsPhotosystem II Protein ComplexProtein ConformationRestriction MappingStructure-Activity Relationship
Identifiers
PMID: 2535507
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ERICKSON, Jeanne Marie et al. Molecular and Biophysical Analysis of Herbicide-Resistant Mutants of Chlamydomonas reinhardtii: Structure-Function Relationship of the Photosystem II D1 Polypeptide. In: Plant Cell, 1989, vol. 1, n° 3, p. 361-371. doi: 10.1105/tpc.1.3.361 https://archive-ouverte.unige.ch/unige:148885

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Deposited on : 2021-02-10

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