Channelrhodopsin-2 Function is Modulated by Residual Hydrophobic Mismatch with the Surrounding Lipid Environment
Channelrhodopsin-2 (ChR2) is a light-gated ion channel that conducts cations of multiple valencies down the electrochemical gradient. This light-gated property has made ChR2 a popular tool in the field of optogenetics, allowing for the spatial and temporal control of excitable cells with light. A ce...
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| Format: | Article |
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MDPI AG
2019-06-01
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| Series: | Applied Sciences |
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| Online Access: | https://www.mdpi.com/2076-3417/9/13/2674 |
| _version_ | 1811208585511698432 |
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| author | Ryan Richards Sayan Mondal Harel Weinstein Robert E. Dempski |
| author_facet | Ryan Richards Sayan Mondal Harel Weinstein Robert E. Dempski |
| author_sort | Ryan Richards |
| collection | DOAJ |
| description | Channelrhodopsin-2 (ChR2) is a light-gated ion channel that conducts cations of multiple valencies down the electrochemical gradient. This light-gated property has made ChR2 a popular tool in the field of optogenetics, allowing for the spatial and temporal control of excitable cells with light. A central aspect of protein function is the interaction with the surrounding lipid environment. To further explore these membrane-protein interactions, we demonstrate the role of residual hydrophobic mismatch (RHM) as a mechanistically important component of ChR2 function. We combined computational and functional experiments to understand how RHM between the lipid environment and ChR2 alters the structural and biophysical properties of the channel. Analysis of our results revealed significant RHM at the intracellular/lipid interface of ChR2 from a triad of residues. The resulting energy penalty is substantial and can be lowered via mutagenesis to evaluate the functional effects of this change in lipid-protein interaction energy. The experimental measurement of channel stability, conductance and selectivity resulting from the reduction of the RHM energy penalty showed changes in progressive H<sup>+</sup> permeability, kinetics and open-state stability, suggesting how the modulation of ChR2 by the surrounding lipid membrane can play an important biological role and contribute to the design of targeted optogenetic constructs for specific cell types. |
| first_indexed | 2024-04-12T04:23:58Z |
| format | Article |
| id | doaj.art-f8a44e6815aa484e95fd70357062f6aa |
| institution | Directory Open Access Journal |
| issn | 2076-3417 |
| language | English |
| last_indexed | 2024-04-12T04:23:58Z |
| publishDate | 2019-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Applied Sciences |
| spelling | doaj.art-f8a44e6815aa484e95fd70357062f6aa2022-12-22T03:48:09ZengMDPI AGApplied Sciences2076-34172019-06-01913267410.3390/app9132674app9132674Channelrhodopsin-2 Function is Modulated by Residual Hydrophobic Mismatch with the Surrounding Lipid EnvironmentRyan Richards0Sayan Mondal1Harel Weinstein2Robert E. Dempski3Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, Worcester, MA 01609, USADepartment of Physiology and Biophysics, Weill Cornell Medical College of Cornell University, New York, NY 10065, USADepartment of Physiology and Biophysics, Weill Cornell Medical College of Cornell University, New York, NY 10065, USADepartment of Chemistry and Biochemistry, Worcester Polytechnic Institute, Worcester, MA 01609, USAChannelrhodopsin-2 (ChR2) is a light-gated ion channel that conducts cations of multiple valencies down the electrochemical gradient. This light-gated property has made ChR2 a popular tool in the field of optogenetics, allowing for the spatial and temporal control of excitable cells with light. A central aspect of protein function is the interaction with the surrounding lipid environment. To further explore these membrane-protein interactions, we demonstrate the role of residual hydrophobic mismatch (RHM) as a mechanistically important component of ChR2 function. We combined computational and functional experiments to understand how RHM between the lipid environment and ChR2 alters the structural and biophysical properties of the channel. Analysis of our results revealed significant RHM at the intracellular/lipid interface of ChR2 from a triad of residues. The resulting energy penalty is substantial and can be lowered via mutagenesis to evaluate the functional effects of this change in lipid-protein interaction energy. The experimental measurement of channel stability, conductance and selectivity resulting from the reduction of the RHM energy penalty showed changes in progressive H<sup>+</sup> permeability, kinetics and open-state stability, suggesting how the modulation of ChR2 by the surrounding lipid membrane can play an important biological role and contribute to the design of targeted optogenetic constructs for specific cell types.https://www.mdpi.com/2076-3417/9/13/2674<i>Chlamydomonas reinhardtii</i>ion channeloptogeneticselectrophysiologymolecular dynamics simulationsmembrane-protein interactionenergy of membrane deformationCTMD method, residual hydrophobic mismatch |
| spellingShingle | Ryan Richards Sayan Mondal Harel Weinstein Robert E. Dempski Channelrhodopsin-2 Function is Modulated by Residual Hydrophobic Mismatch with the Surrounding Lipid Environment Applied Sciences <i>Chlamydomonas reinhardtii</i> ion channel optogenetics electrophysiology molecular dynamics simulations membrane-protein interaction energy of membrane deformation CTMD method, residual hydrophobic mismatch |
| title | Channelrhodopsin-2 Function is Modulated by Residual Hydrophobic Mismatch with the Surrounding Lipid Environment |
| title_full | Channelrhodopsin-2 Function is Modulated by Residual Hydrophobic Mismatch with the Surrounding Lipid Environment |
| title_fullStr | Channelrhodopsin-2 Function is Modulated by Residual Hydrophobic Mismatch with the Surrounding Lipid Environment |
| title_full_unstemmed | Channelrhodopsin-2 Function is Modulated by Residual Hydrophobic Mismatch with the Surrounding Lipid Environment |
| title_short | Channelrhodopsin-2 Function is Modulated by Residual Hydrophobic Mismatch with the Surrounding Lipid Environment |
| title_sort | channelrhodopsin 2 function is modulated by residual hydrophobic mismatch with the surrounding lipid environment |
| topic | <i>Chlamydomonas reinhardtii</i> ion channel optogenetics electrophysiology molecular dynamics simulations membrane-protein interaction energy of membrane deformation CTMD method, residual hydrophobic mismatch |
| url | https://www.mdpi.com/2076-3417/9/13/2674 |
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