The photoreaction of vacuum-dried rhodopsin at low temperature: Evidence for charge stabilization by water
✍ Scribed by U.M. Ganter; E.D. Schmid; F. Siebert
- Publisher
- Elsevier Science
- Year
- 1988
- Tongue
- English
- Weight
- 639 KB
- Volume
- 2
- Category
- Article
- ISSN
- 1011-1344
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✦ Synopsis
The photoreaction of vacuum-dried rhodopsin was monitored by UV-visible absorption spectroscopy. The results indicate that in dry rhodopsin, isorhodopsin and lumirhodopsin a protonation equilibrium exists between the protonated and the non-protonated Schiff base. On hydration the water stabilizes the protonated forms. In metarhodopsin-I the protein itself is able to stabilize the protonated Schiff base. The direct involvement of water in the retinal binding site was demonstrated by measuring the rhodopsin-bathorhodopsin FTIR difference spectra of rhodopsin hydrated with H2O and H2(18)O. The results are discussed with respect to the problem of charge stabilization and energy storage.