Structural Insights Into the Opening Mechanism of C1C2 Channelrhodopsin
Matthias Mulder1, Songhwan Hwang2,3, Matthias Broser3
1PSI Center for Life Sciences, Laboratory for Biomolecular Research, Paul Scherrer Institut, Villigen 5232, Switzerland.
Journal of the American Chemical Society
|December 16, 2024
Summary
This study reveals how C1C2 channelrhodopsin opens using time-resolved crystallography and simulations. Structural changes in key intermediates facilitate cation flow, advancing optogenetics research.
Area of Science:
- Optogenetics
- Structural Biology
- Biophysics
Background:
- Channelrhodopsins are light-gated ion channels crucial for optogenetics.
- Understanding their activation mechanism is key to precise neural control.
Purpose of the Study:
- To elucidate the structural dynamics of C1C2 channelrhodopsin activation.
- To identify structural changes during key intermediate states.
Main Methods:
- Time-resolved serial crystallography
- Atomistic molecular dynamics (MD) simulations
Main Results:
- C1C2 predominantly adopts a light-activated M390 intermediate state in crystals.
- Retinal rearrangement and partial opening of the central gate were observed.
- MD simulations of the N520 intermediate revealed transmembrane helix rearrangements, opening the inner gate and ion pathway.
- Spontaneous cation conduction with low conductance was enabled.
Conclusions:
- The study provides atomistic insights into channelrhodopsin gating mechanisms.
- Identified structural transitions explain ion conduction and selectivity.
- Enhances understanding of optogenetic tools at a molecular level.
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