Calcium, conformational selection, and redox-active tyrosine YZ in the photosynthetic oxygen-evolving cluster
نویسندگان
چکیده
منابع مشابه
Proximity of the manganese cluster of photosystem II to the redox-active tyrosine YZ.
Electron spin echo electron-nuclear double resonance (ESE-ENDOR) experiments performed on a broad radical electron paramagnetic resonance (EPR) signal observed in photosystem II particles depleted of Ca2+ indicate that this signal arises from the redox-active tyrosine YZ. The tyrosine EPR signal width is increased relative to that observed in a manganese-depleted preparation due to a magnetic i...
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...
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Manganese redox enzymes play crucial roles in a variety of biological systems. These include the photosynthetic oxidation of water m dioxygen, the disproport ionat ion of hydrogen peroxide, the disproport ionat ion of superoxide, and ribonucleotide reduction. The Mn sites in two of these systems, the photosynthetic oxygen evolving complex (OEC) and the Mn catalase from L. planrarum have been ch...
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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 کاملMultiple redox-active chlorophylls in the secondary electron-transfer pathways of oxygen-evolving photosystem II.
Photosystem II (PS II) is unique among photosynthetic reaction centers in having secondary electron donors that compete with the primary electron donors for reduction of P680(+). We have characterized the photooxidation and dark decay of the redox-active accessory chlorophylls (Chl) and beta-carotenes (Car) in oxygen-evolving PS II core complexes by near-IR absorbance and EPR spectroscopies at ...
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ژورنال
عنوان ژورنال: Proceedings of the National Academy of Sciences
سال: 2018
ISSN: 0027-8424,1091-6490
DOI: 10.1073/pnas.1800758115