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Updated: Jun 23, 2025
10:03
Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy
Published on: June 27, 2014
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Structural Models of the First Molecular Events in the Heliorhodopsin Photocycle
Kithmini Wijesiri1, José A Gascón1
1Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269-3060, United States.
The Journal of Physical Chemistry. B
|June 14, 2024
Summary
Key rearrangements in Heliorhodopsin
Area of Science:
- Biophysics
- Computational Chemistry
- Structural Biology
Background:
- The Heliorhodopsin photocycle involves proton transfer crucial for its function.
- Understanding retinylidene conformations and hydrogen-bond network dynamics is essential.
Purpose of the Study:
- To model photoisomerization and early intermediates in Heliorhodopsin.
- To elucidate the role of retinylidene conformations and proton transfer mechanisms.
Main Methods:
- Molecular dynamics simulations
- Quantum mechanical/molecular mechanics (QM/MM) calculations
- Metadynamics simulations
Main Results:
- Modeled photoisomerized intermediates with specific retinylidene conformations (13-cis).
- Identified rearrangements around C13=C14 and C15=N bonds.
- Demonstrated how structural changes favor Schiff base deprotonation and counterion protonation.
Conclusions:
- Retinylidene conformations and hydrogen-bond network rearrangements are critical for Heliorhodopsin's proton transfer.
- These structural dynamics facilitate key steps in the photocycle, including Schiff base deprotonation.
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