Activation of rhodopsin by light, molecular model
Bildnummer 13436195
| Molecular model showing the activation of rhodopsin by light in a photoreceptor cell. Rhodopsin (purple, top centre) is a light sensitive G-protein coupled receptor (GPCR) with retinal (red) as a cofactor. When light hits rhodopsin it causes a change in shape in retinal. This stimulates the G-protein transducin (blue, lower left). Transducin's alpha subunit (light blue) exchanges its bound molecule of GDP (guanosine diphosphate, yellow) for a molecule of GTP (guanosine triphosphate, dark orange). This releases the G-alpha subunit, leaving it free to activate the enzyme phosphodiesterase (PDE6). Phosphodiesterase hydrolyses cGMP, decreasing cGMP levels. This causes the closure of sodium channels causing the outer segment membrane of photoreceptor cells to become hyperpolarised. | |
| Lizenzart: | Lizenzfrei |
| Credit: | Science Photo Library / Gaertner, Juan |
| Modell-Rechte: | nicht erforderlich |
| Eigentums-Rechte: | nicht erforderlich |
| Restrictions: | - |
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