scholarly journals Photoinactivation of Photosystem II Induces Changes in the Photochemical Reaction Center II Abolishing the Regulatory Role of the Qb Site in the Dl Protein Degradation

2008 ◽  
Vol 231 (2) ◽  
pp. 448-453
Author(s):  
Hagit Zer ◽  
Itzhak Ohad
Keyword(s):  
Photosystem Ii ◽  
Protein Degradation ◽  
Reaction Center ◽  
Photochemical Reaction ◽  
Regulatory Role

Role of an Extrinsic 33 Kilodalton Protein of Photosystem II in the Turnover of the Reaction Center-Binding Protein D1 during Photoinhibition†

Biochemistry ◽  
1998 ◽  
Vol 37 (6) ◽  
pp. 1565-1574 ◽  
Author(s):  
Yasusi Yamamoto ◽  
Yasuo Ishikawa ◽  
Etsuko Nakatani ◽  
Mina Yamada ◽  
Haoming Zhang ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Reaction Center ◽  
Binding Protein

scholarly journals Early Archean origin of Photosystem II

2017 ◽  
Author(s):  
Tanai Cardona ◽  
Patricia Sánchez-Baracaldo ◽  
A. William Rutherford ◽  
Anthony W. D. Larkum
Keyword(s):  
Photosystem Ii ◽  
Reaction Center ◽  
Water Oxidation ◽  
Photochemical Reaction ◽  
Early Stage ◽  
Oxygenic Photosynthesis ◽  
Recent Common Ancestor ◽  
Molecular Clocks ◽  
Most Recent Common Ancestor ◽  
History Of

AbstractPhotosystem II is a photochemical reaction center that catalyzes the light-driven oxidation of water to molecular oxygen. Water oxidation is the distinctive photochemical reaction that permitted the evolution of oxygenic photosynthesis and the eventual rise of Eukaryotes. At what point during the history of life an ancestral photosystem evolved the capacity to oxidize water still remains unknown. Here we study the evolution of the core reaction center proteins of Photosystem II using sequence and structural comparisons in combination with Bayesian relaxed molecular clocks. Our results indicate that a homodimeric photosystem with sufficient oxidizing power to split water had already appeared in the early Archean about a billion years before the most recent common ancestor of all described Cyanobacteria capable of oxygenic photosynthesis, and well before the diversification of some of the known groups of anoxygenic photosynthetic bacteria. Based on a structural and functional rationale we hypothesize that this early Archean photosystem was capable of water oxidation and had already evolved some level of protection against the formation of reactive oxygen species, which would place primordial forms of oxygenic photosynthesis at a very early stage in the evolutionary history of life.

Two-Step Mechanism of Photodamage to Photosystem II:  Step 1 Occurs at the Oxygen-Evolving Complex and Step 2 Occurs at the Photochemical Reaction Center†

Biochemistry ◽  
2005 ◽  
Vol 44 (23) ◽  
pp. 8494-8499 ◽  
Author(s):  
Norikazu Ohnishi ◽  
Suleyman I. Allakhverdiev ◽  
Shunichi Takahashi ◽  
Shoichi Higashi ◽  
Masakatsu Watanabe ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Reaction Center ◽  
Photochemical Reaction ◽  
Oxygen Evolving Complex ◽  
Oxygen Evolving ◽  
Step Mechanism

scholarly journals Separate photosensitizers mediate degradation of the 32-kDa photosystem II reaction center protein in the visible and UV spectral regions

1989 ◽  
Vol 86 (17) ◽  
pp. 6617-6620 ◽  
Author(s):  
B M Greenberg ◽  
V Gaba ◽  
O Canaani ◽  
S Malkin ◽  
A K Mattoo ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Photosystem Ii ◽  
Protein Degradation ◽  
Reaction Center ◽  
Spectral Range ◽  
Photosynthetic Pigments ◽  
Redox States ◽  
Reaction Center Protein ◽  
Broad Spectral Range ◽  
Uv Visible

A component of the photosystem II reaction center, the 32-kDa protein, is rapidly turned over in the light. The mechanism of its light-dependent metabolism is largely unknown. We quantified the rate of 32-kDa protein degradation over a broad spectral range (UV, visible, and far red). The quantum yield for degradation was highest in the UVB (280-320 nm) region. Spectral evidence demonstrates two distinctly different photosensitizers for 32-kDa protein degradation. The data implicate the bulk photosynthetic pigments (primarily chlorophyll) in the visible and far red regions, and plastoquinone (in one or more of its redox states) in the UV region. A significant portion of 32-kDa protein degradation in sunlight is attributed to UVB irradiance.

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