The chloride requirement for photosynthetic oxygen evolution: Factors affecting nucleophilic displacement of chloride from the oxygen-evolving complex
نویسندگان
چکیده
منابع مشابه
OXYGEN EVOLUTION IN PHOTOSYNTHESIS 683 Chloride Requirement for Oxygen Evolution in Photosynthesis
The role of chloride in photosynthetic oxygen evolution was reinvestigated by determining the effect of this ion on photochemical reactions of chloroplasts in which oxygen either is or is not produced. The chloroplasts used were isolated from normal spinach leaves. The level of chloride in the reaction mixture was controlled by washing the isolated chloroplasts and by avoiding a chloride contam...
متن کاملCHLORIDE REQUIREMENT IN PHOTOSYSTEM II AND ANION EFFECTS IN THE S2’ STATE OF THE OXYGEN EVOLVING COMPLEX By
The oxygen evolving complex (OEC) of photosystem II (PSII) requires chloride as a critical cofactor. The Cl content of PSII was determined to be 1 Cl/PSII by the AgCl colloid assay. The dissociation constant for Cl in NaCl-washed PSII was determined using the Cl sensitive microelectrode. Two classes of Cl binding sites were found with Kd values of 53 μM and 4.2 mM. The effects of anions on the ...
متن کاملXAS of Mn in the Photosynthetic Oxygen, Evolving Complex
Nearly all of the dioxygen which animals and aerobic bacteria use during respiration originates from the photosynthetic oxygen evolving complex (OEC) which is found in the chloroplast thylakoid membranes of higher plants and algae. Four specifically bound Mn are required for OEC activity [l]. These manganese do not exhibit the six line epr spectrum which is characteristic of Mn(IIj in solution,...
متن کاملCI-NMR measurement of chloride binding to the oxygen-evolving complex of spinach Photosystem II
The mechanism by which CIactivates the oxygen-evolving complex (OEC) of Photosystem II (PS II) in spinach was studied by 3SCI-NMR spectroscopy and steady-state measurements of oxygen evolution. Measurements of the excess 35Cl-NMR linewidth in dark-adapted, CI--depleted thylakoid and Photosystem I1 membranes show an overall hyperbolic decrease which is interrupted by sharp increases in linewidth...
متن کاملArchitecture of the photosynthetic oxygen-evolving center.
Photosynthesis uses light energy to drive the oxidation of water at an oxygen-evolving catalytic site within photosystem II (PSII). We report the structure of PSII of the cyanobacterium Thermosynechococcus elongatus at 3.5 angstrom resolution. We have assigned most of the amino acid residues of this 650-kilodalton dimeric multisubunit complex and refined the structure to reveal its molecular ar...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Biochimica et Biophysica Acta (BBA) - Bioenergetics
سال: 1986
ISSN: 0005-2728
DOI: 10.1016/0005-2728(86)90099-x