Raman microscope and quantum yield studies on the primary photochemistry of A2-visual pigments
| Autor: | Richard A. Mathies, B. Barry, Johan Lugtenburg, J. A. Pardoen |
|---|---|
| Rok vydání: | 1987 |
| Předmět: |
Rhodopsin
Opsin Photochemistry 030303 biophysics Analytical chemistry Biophysics Quantum yield In Vitro Techniques Spectrum Analysis Raman 03 medical and health sciences chemistry.chemical_compound symbols.namesake Goldfish Animals Photoreceptor Cells 030304 developmental biology 0303 health sciences biology Scattering Retinal Chromophore chemistry biology.protein symbols Cattle Raman microscope sense organs Raman spectroscopy Retinal Pigments Research Article |
| Zdroj: | Biophysical Journal. 52(4):603-610 |
| ISSN: | 0006-3495 |
| DOI: | 10.1016/s0006-3495(87)83250-2 |
| Popis: | The 77-K resonance Raman vibrational spectrum of intact goldfish rod photoreceptors containing 3,4-dehydro (A2) retinal is dominated by scattering from the 9-cis component of the steady state at all excitation wavelengths. Intact goldfish photoreceptors were regenerated with an A1-retinal chromophore to determine whether this behavior is caused by the protein or the chromophore. The resulting Raman spectrum was typical of an A1-pigment exhibiting significant scattering from all three components of the steady state: rhodopsin, bathorhodopsin, and isorhodopsin. Furthermore, regeneration of bovine opsin with A2-retinal produces a characteristic "A2-Raman spectrum" that is dominated by scattering from the 9-cis pigment. We conclude that the differences between the Raman spectra of the A1-and A2-pigments are caused by some intrinsic difference in the photochemical properties of the retinal chromophores. To quantitate these observations, the 77-K adsorption spectra and the photochemical quantum yields (phi) of the native A2-goldfish and the regenerated A2-bovine pigments were measured. In the goldfish A2-pigment, the value of phi 4 (9-cis----trans) is 0.05; phi 3 (trans----9-cis) is 0.10; and phi 2 (trans----11-cis) is 0.35. By contrast, in the bovine A1-pigment, these quantum yields are 0.10, 0.053, and 0.50, respectively. The reduced value of phi 4 and the increased value of phi 3 in the goldfish pigment confirms that the 9-cis isomer is photochemically more stable in A2-pigments. |
| Databáze: | OpenAIRE |
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