Enhancement of opsin activity by all-trans-retinal.
Exp Eye Res
; 66(5): 599-603, 1998 May.
Article
en En
| MEDLINE
| ID: mdl-9628807
ABSTRACT
The rod cell photoreceptor apoprotein, opsin, activates the G-protein, transducin, although at a much reduced level than light-activated rhodopsin. The ability of all-trans-retinal to enhance opsin apoprotein activity was investigated using a guanyl nucleotide exchange assay on transducin. All-trans-retinal enhanced opsin activity in a concentration-dependent manner. At high concentrations of all-trans-retinal, the activity of the all-trans-retinal-opsin complex was comparable to that from an equimolar amount of metarhodopsin(II). However, in contrast to metarhodopsin(II), the active all-trans-retinalopsin complex did not require a stable Schiff base linkage between opsin and all-trans-retinal. The lack of a stable Schiff base and differences in activity at high pH imply that opsin and all-trans-retinal form a complex that is distinct from metarhodopsin(II). The ability of all-trans-retinal to stimulate the transduction cascade may be a source of post-bleach noise in photoreceptors.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Retinaldehído
/
Segmento Externo de la Célula en Bastón
/
Opsinas de Bastones
Límite:
Animals
Idioma:
En
Revista:
Exp Eye Res
Año:
1998
Tipo del documento:
Article
País de afiliación:
Estados Unidos