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Published on: May 29, 2018
Light-induced structural changes in a photosynthetic reaction center caught by Laue diffraction
Annemarie B Wöhri1, Gergely Katona, Linda C Johansson
1Department of Chemical and Biological Engineering, Chalmers University of Technology, Box 462, SE-40530 Göteborg, Sweden.
Science (New York, N.Y.)
|May 1, 2010
Summary
Researchers studied light-induced conformational changes in photosynthetic reaction centers. They found a tyrosine residue moves, stabilizing energy conversion in photosynthesis.
Area of Science:
- Biophysics
- Photosynthesis research
- Structural biology
Background:
- Photosynthetic reaction centers are crucial for converting light energy into biochemical energy.
- They establish a transmembrane potential, forming the primary energy input pathway for the biosphere.
- Understanding their conformational dynamics is key to elucidating energy conversion mechanisms.
Purpose of the Study:
- To investigate light-induced conformational changes in the photosynthetic reaction center complex of Blastochloris viridis.
- To determine the role of specific amino acid residues in the primary photoactivation events.
- To elucidate the mechanism of energy stabilization during photosynthesis.
Main Methods:
- Time-resolved Laue diffraction was employed to capture rapid structural changes.
- Analysis focused on the photosynthetic reaction center complex from Blastochloris viridis.
- Free energy calculations were used to model molecular movements and their energetic implications.
Main Results:
- A significant conformational change was observed in the TyrL162 side chain, moving 1.3 angstroms closer to the special pair.
- This movement was triggered by photoactivation of the reaction center.
- Calculations indicated deprotonation of the tyrosine residue as the cause of the movement.
Conclusions:
- The observed movement of TyrL162 is a direct consequence of photoactivation and deprotonation.
- This conformational change provides a mechanism for stabilizing the critical charge separation events in photosynthesis.
- The findings offer insights into the efficiency and regulation of biological light energy conversion.
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