Interaction of 11-cis-Retinol Dehydrogenase with the Chromophore of Retinal G Protein-coupled Receptor Opsin
| Autor: | Pu Chen, Henry K.W. Fong, Terry D. Lee |
|---|---|
| Rok vydání: | 2001 |
| Předmět: |
Opsin
Light genetic structures Photoisomerization Molecular Sequence Data Receptors Cell Surface Dehydrogenase Biochemistry Mass Spectrometry Retina Cofactor Receptors G-Protein-Coupled Substrate Specificity chemistry.chemical_compound medicine Animals Trypsin Amino Acid Sequence Retinal G protein coupled receptor Eye Proteins Pigment Epithelium of Eye Vitamin A Molecular Biology Chromatography High Pressure Liquid Binding Sites Retinal pigment epithelium biology Rod Opsins Retinal Cell Biology Darkness NAD Peptide Fragments eye diseases Alcohol Oxidoreductases Kinetics medicine.anatomical_structure chemistry Retinaldehyde biology.protein Cattle sense organs NADP Visual phototransduction |
| Zdroj: | Journal of Biological Chemistry. 276:21098-21104 |
| ISSN: | 0021-9258 |
| DOI: | 10.1074/jbc.m010441200 |
| Popis: | Vertebrate opsins in both photoreceptors and the retinal pigment epithelium (RPE) have fundamental roles in the visual process. The visual pigments in photoreceptors are bound to 11-cis-retinal and are responsible for the initiation of visual excitation. Retinochrome-like opsins in the RPE are bound to all-trans-retinal and play an important role in chromophore metabolism. The retinal G protein-coupled receptor (RGR) of the RPE and Müller cells is an abundant opsin that generates 11-cis-retinal by stereospecific photoisomerization of its bound all-trans-retinal chromophore. We have analyzed a 32-kDa protein (p32) that co-purifies with bovine RGR from RPE microsomes. The co-purified p32 was identified by mass spectrometric analysis as 11-cis-retinol dehydrogenase (cRDH), and enzymatic assays have confirmed the isolation of an active cRDH. The co-purified cRDH showed marked substrate preference to 11-cis-retinal and preferred NADH rather than NADPH as the cofactor in reduction reactions. cRDH did not react with endogenous all-trans-retinal bound to RGR but reacted specifically with 11-cis-retinal that was generated by photoisomerization after irradiation of RGR. The reduction of 11-cis-retinal to 11-cis-retinol by cRDH enhanced the net photoisomerization of all-trans-retinal bound to RGR. These results indicate that cRDH is involved in the processing of 11-cis-retinal after irradiation of RGR opsin and suggest that cRDH has a novel role in the visual cycle. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|