11-cis retinal binding

Definition

Target type: molecularfunction

Binding to 11-cis retinal, an isomer of retinal that plays an important role in the visual process in most vertebrates. 11-cis retinal combines with opsin in the rods (scotopsin) to form rhodopsin or visual purple. Retinal is one of the three compounds that makes up vitamin A. [PMID:24403072]

11-cis retinal binding is a crucial molecular function in the visual cycle, responsible for the conversion of light energy into an electrical signal in the retina. The process begins with the binding of 11-cis retinal to the protein opsin, forming rhodopsin. When light strikes rhodopsin, it causes a conformational change in the 11-cis retinal, isomerizing it to all-trans retinal. This isomerization triggers a cascade of events that ultimately leads to the activation of a signaling pathway within the photoreceptor cell. The key steps in this process include:

1. **Light Absorption:** When light hits rhodopsin, the energy is absorbed by the 11-cis retinal, causing it to isomerize into all-trans retinal.
2. **Conformational Change:** The isomerization of retinal induces a conformational change in the opsin protein, transitioning it from its inactive state to an active form.
3. **Activation of Signaling Pathway:** This conformational change in opsin activates a G-protein called transducin. Activated transducin then activates an enzyme called phosphodiesterase, which hydrolyzes cyclic GMP. This reduction in cyclic GMP levels triggers a cascade of events leading to the closure of sodium channels in the photoreceptor cell membrane.
4. **Hyperpolarization:** The closure of sodium channels reduces the influx of sodium ions into the photoreceptor cell, leading to hyperpolarization of the cell membrane. This change in membrane potential is the electrical signal that is transmitted to the brain, enabling vision.

In summary, 11-cis retinal binding serves as the primary trigger for light-induced signaling in photoreceptor cells, converting light energy into a chemical signal that can be processed by the nervous system. The binding of 11-cis retinal to opsin is essential for the proper function of vision.'
"

Proteins (1)

Compounds (2)