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Functional and structural analysis of photosystem II core complexes from spinach with high oxygen evolution capacity
E Haag1, K D Irrgang, E J Boekema
1Max-Volmer-Institut für Biophysikalische und Physikalische Chemie, Technische Universität Berlin.
European Journal of Biochemistry
|April 20, 1990
Summary
Researchers purified oxygen-evolving photosystem II core complexes from spinach, revealing their structure and function. The extrinsic 33-kDa protein was visualized for the first time, offering new insights into photosystem II structure.
Area of Science:
- Biochemistry
- Plant Physiology
- Structural Biology
Background:
- Photosystem II (PSII) is crucial for oxygenic photosynthesis.
- Understanding the structure of PSII core complexes is vital for elucidating its function.
Purpose of the Study:
- To prepare and characterize oxygen-evolving photosystem II core complexes from spinach.
- To determine the structural and functional properties of these complexes, including the visualization of the extrinsic 33-kDa protein.
Main Methods:
- Solubilization of photosystem II membrane fragments using dodecyl-beta-D-maltoside.
- Biochemical assays to measure oxygen evolution rates.
- Electron microscopy for structural analysis.
Main Results:
- Purified core complexes exhibited high oxygen evolution rates.
- Electron microscopy revealed an obtuse triangular structure (15.3 nm x 10.6 nm) with a height of 7.3 nm.
- The extrinsic 33-kDa protein was visualized as a protrusion, suggesting its role in covering the lumenal side.
Conclusions:
- The study successfully prepared and characterized functional spinach photosystem II core complexes.
- The visualization of the 33-kDa protein provides new structural information about the lumenal side of PSII.
- The findings align with previous structural data while offering novel insights.