An exploration of the algal protein channelrhodospin and the origins of optogenetics

Abstract

Channelrhodopsin (ChR) is a light‐gated cation channel protein originally discovered in the algae Chlamydomonas reinhardtii. Composed of seven transmembrane helices (TM1‐7) covalently bound to all‐trans retinal (ATR), ChR permits cations to pass through cellular membranes when excited by light, functioning in algal photoreception. During excitation, ATR undergoes photoisomerization into the 13‐cis retinal form, triggering conformational changes that transfer protons between the protonated retinal Schiff base and its residue counterions. These protonation events control gating of the electronegative pore formed by TM1, 2, 3, and 7, allowing selective cation passage regulated by TM2 while excited, before thermally cycling back to ground state. The Blue Valley CAPS 2017–18 MSOE Center for BioMolecular Modeling SMART Team modeled channelrhodopsin chimaera C1C2 using JMol and 3D printing technology with the goal of exploring this protein's unique properties as utilized in the revolutionary field of optogenetics. Optogenetics uses light and genetic engineering to systematically target and manipulate cellular systems in living organisms, enabling unprecedented research and experimentation in disciplines such as neuroscience. Through Cre‐Lox site‐specific recombinase and adeno‐associated viral technology, researchers can express ChR in specific neurons, allowing light‐based experimental control of neural pathways and action potentials. Studies done with these techniques have shed new light onto neurological and psychiatric disorders, and could potentially hold the key to new effective treatment options.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.