Red-sensitive opsin is a protein that in humans is encoded by the OPN1LWgene.[5]
Function
This gene encodes for a light absorbing visual pigment of the opsin gene family. The encoded protein is called redconephotopigment or long-wavelength sensitive opsin (LWS opsin or L opsin). Contrary to popular belief, the human red-sensitive opsin's peak response is not in the red region of the visual spectrum; its peak sensitivity is 560 nm, which corresponds to a "yellowish-green" color, i.e. between green (530 nm) and yellow (580 nm).[6] Its name as the "red" opsin reflects the fact that it is more sensitive to red than the other two human opsins. The red opsin also has a secondary response in the violet high frequencies.[7]
Opsins are G-protein coupled receptors with seven transmembrane domains, an N-terminal extracellular domain, and a C-terminal cytoplasmic domain. This gene and the medium-wavelength opsin gene are tandemly arrayed on the X chromosome and frequent unequal recombination and gene conversion may occur between these sequences. X chromosomes may have fusions of the medium- and long-wavelength opsin genes or may have more than one copy of these genes. Defects in this gene are the cause of partial, protanopic colorblindness.[5]
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