Vitamin A(1)/A(2) chromophore exchange: its role in spectral tuning and visual plasticity
| Autor: | Joseph C. Corbo |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Opsin
genetic structures Sensory system Retinal Pigment Epithelium Biology Article Retina 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine food Retinal Rod Photoreceptor Cells medicine Animals Vitamin A Molecular Biology 030304 developmental biology Vitamin a1 0303 health sciences Retinal pigment epithelium Opsins Rod Opsins Retinal Cell Biology Chromophore Spectral sensitivity medicine.anatomical_structure chemistry Biophysics Retinal Cone Photoreceptor Cells food.nutrient sense organs Retinal Pigments 030217 neurology & neurosurgery Developmental Biology Photoreceptor Cells Vertebrate |
| Zdroj: | Dev Biol |
| Popis: | Vertebrate rod and cone photoreceptors detect light via a specialized organelle called the outer segment. This structure is packed with light-sensitive molecules known as visual pigments that consist of a G-protein-coupled, seven-transmembrane protein known as opsin, and a chromophore prosthetic group, either 11-cis retinal (‘A(1)’) or 11-cis 3,4-didehydroretinal (‘A(2)’). The enzyme cyp27c1 converts A(1) into A(2) in the retinal pigment epithelium. Replacing A(1) with A(2) in a visual pigment red-shifts its spectral sensitivity and broadens its bandwidth of absorption at the expense of decreased photosensitivity and increased thermal noise. The use of vitamin A(2)-based visual pigments is strongly associated with the occupation of turbid aquatic habitats in which the ambient light is red-shifted. By modulating the A(1)/A(2) ratio in the retina, an organism can dynamically tune the spectral sensitivity of the visual system to match the predominant wavelengths of light in its environment. As many as a quarter of all vertebrate species utilize A(2), during part of their life cycle or under certain environmental conditions. A(2) utilization therefore represents an important and widespread mechanism of sensory plasticity. This review provides an up-to-date account of the A(1)/A(2) chromophore exchange system. |
| Databáze: | OpenAIRE |
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