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Multiple crystal types reveal photosystem II to be a dimer
1Department of Molecular, Cellular and Developmental Biology, Campus Box 347, University of Colorado, Boulder, CO 80307, USA. mkl@demeter.colorado.edu
Biochimica Et Biophysica Acta
|June 19, 1998
Summary
Photosystem II (PS II) was crystallized and analyzed using electron microscopy. Results indicate PS II functions as a dimer, with potential variations in its reaction center cores.
Area of Science:
- Biochemistry
- Structural Biology
- Photosynthesis Research
Background:
- Photosystem II (PS II) is a crucial protein complex in oxygenic photosynthesis, responsible for light-driven water oxidation.
- Understanding the structural organization of PS II is essential for elucidating its mechanism and improving photosynthetic efficiency.
Purpose of the Study:
- To determine the quaternary structure of Photosystem II (PS II).
- To generate high-resolution structural information of PS II using crystallographic methods.
Main Methods:
- Crystallization of Photosystem II (PS II) using various detergents.
- Analysis of crystal structures via electron microscopy and image processing.
- Determination of two-fold symmetry using difference maps.
Main Results:
- Three types of PS II crystals were produced, yielding projection maps.
- Highest resolution data obtained from type 1 and type 2 crystals.
- Structural analysis revealed a high degree of two-fold symmetry, suggesting PS II is a dimer.
Conclusions:
- Photosystem II (PS II) exists as a dimer.
- The two reaction center cores within the dimer may possess slightly different antenna polypeptide compositions.