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ATP‐induced photochemical quenching of variable chlorophyll fluorescence
Author(s) -
Schreiber U.,
Rienits K.G.
Publication year - 1987
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(87)81282-6
Subject(s) - quenching (fluorescence) , photochemistry , chemistry , thylakoid , fluorescence , photosystem ii , atpase , electron transport chain , chloroplast , biophysics , chlorophyll fluorescence , photosystem , photosynthesis , biochemistry , enzyme , biology , physics , quantum mechanics , gene
ATP induces rapid quenching of fluorescence yield in light‐activated class D chloroplasts, distinguishable from the slower quenching caused by protein phosphorylation. The mechanism of the rapid quenching is shown to be photochemical, by application of the saturation pulse method with a modulated measuring system [(1986) Photosynth. Res. 10, 51‐62]. The effect is most pronounced at relatively low light intensities (optimum 2) without addition of electron acceptors. The properties of the ATP‐induced quenching with respect to ionophores, uncouplers and ATPase inhibitors suggest involvement of the reversible, light‐activated thylakoid ATPase. As a working hypothesis, it is proposed that part of PS II reaction centers, which are stroma‐exposed and in close proximity to CF 0 ‐CF 1 , are modified by ATPase activity. Transformation of cytochrome b ‐559 high‐potential form to low‐potential form by membrane acidification is discussed as a possible mechanism.