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Updated: Nov 14, 2025
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Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy
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Channelrhodopsin C1C2: Photocycle kinetics and interactions near the central gate
Monika R VanGordon1, Lindsey A Prignano2, Robert E Dempski2
1Department of Chemistry, University of New Orleans, New Orleans, Louisiana.
Biophysical Journal
|March 11, 2021
Summary
Channelrhodopsins (ChR) are light-sensitive proteins controlling cells. This study reveals how mutations alter channel gating at a molecular level using atomistic simulations and experimental rates.
Area of Science:
- Optogenetics
- Biophysics
- Molecular Biology
Background:
- Channelrhodopsins (ChR) are light-gated ion channels crucial for optogenetics.
- Understanding how mutations affect ChR molecular dynamics and gating is essential.
Purpose of the Study:
- To investigate the molecular basis of gating kinetics in a ChR chimera (C1C2) and its variants.
- To correlate experimental channel kinetics with atomistic simulation data.
Main Methods:
- Measurement of channel opening and closing rates for C1C2 and variants (N297D, N297V, V125L).
- Atomistic simulations to analyze pore structure, hydration, and residue interactions.
- Investigating the role of 13-cis retinal, E129 deprotonation, and N297 interactions.
Main Results:
- C1C2 and its mutants exhibit unique gating properties distinct from ChR2, except for V125L.
- Channel opening involves hydration of gating regions and deprotonation of E129.
- A specific hydrogen bond weakening between E129 and N297 facilitates channel opening.
- Aspartate D292 acts as the primary proton acceptor for the retinal Schiff base.
Conclusions:
- The study elucidates the molecular mechanisms underlying channelrhodopsin gating.
- Atomistic simulations provide insights into how mutations influence channel kinetics and structure.
- C1C2 serves as a unique model for studying channelrhodopsin function and gating mechanisms.
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