Determination of chromophore structure and environment in bovine visual pigments with resonance Raman spectroscopy
Resonance Raman spectra of /sup 2/H- and /sup 13/C-labeled visual pigments have been obtained and analyzed. The C-C stretching vibrations of rhodopsin, isorhodopsin, and bathorhodopsin have been assigned, as well as those of the 11-cis and 9-cis retinal protonated Schiff base model compounds. The insensitivity of the C/sub 14/-C/sub 15/ stretch frequency to N-deuteration in all three pigments demonstrates that each contains a trans C=N bond. Comparison of the fingerprint modes of the visual pigments and their model compounds shows that the C/sub 10/-C/sub 11/ and C/sub 14/-C/sub 15/ single bonds are s-trans in all three pigments. This provides evidence against the model of bathorhodopsin proposed by Lui and Asato, which suggests a C/sub 10/-C/sub 11/ s-cis structure. The extreme similarity of the C-C stretch modes of rhodopsin and the 11-cis retinal protonated Schiff base argues against the presence of a negatively charged protein residue near C/sub 13/, proposed to be responsible for the opsin shift of rhodopsin. However, the unusually large shift of the C=N stretch frequency upon N-deuteration in rhodopsin relative to the model compound suggests that the opsin shift mechanism may involve altered Schiff base - counter ion interactions.
- Research Organization:
- California Univ., Berkeley (USA)
- OSTI ID:
- 7002251
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
RHODOPSIN
MOLECULAR STRUCTURE
CARBON 13
CATTLE
DEUTERIUM
PIGMENTS
RAMAN SPECTRA
SCHIFF BASES
TRACER TECHNIQUES
ANIMALS
CARBON ISOTOPES
DOMESTIC ANIMALS
EVEN-ODD NUCLEI
HYDROGEN ISOTOPES
IMINES
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
MAMMALS
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PROTEINS
RUMINANTS
SPECTRA
STABLE ISOTOPES
VERTEBRATES
550201* - Biochemistry- Tracer Techniques