Abstract Opsins are G protein-coupled receptors (GPCRs) that have evolved to detect light stimuli and initiate intracellular signaling cascades. Their role as signal transducers is critical to light perception across the animal kingdom. Opsins covalently bind to the chromophore 11-cis retinal. which isomerizes to the all-trans isomer upon photon absorption. https://pyrodresoners.shop/product-category/3d-tpu-parts/