Low-temperature solid-state /sup 13/C NMR studies of the retinal chromophore in rhodopsin

Journal Article · Tue Mar 24 04:00:00 EST 1987 · Biochemistry; (United States)

OSTI ID:6469727

Smith, S O; Palings, I; Copie, V; Raleigh, D P; Courtin, J; Pardoen, J A; Lugtenburg, J; Mathies, R A; Griffin, R G

Magic angle sample spinning (MASS) /sup 13/C NMR spectra have been obtained of bovine rhodopsin regenerated with retinal prosthetic groups isotopically enriched with /sup 13/C at C-5 and C-14. In order to observe the /sup 13/C retinal chromophore resonances, it was necessary to employ low temperatures (-15 ..-->.. -35/sup 0/C) to restrict rotational diffusion of the protein. The isotropic chemical shift and principal values of the chemical shift tensor of the /sup 13/C-5 label indicate that the retinal chromophore is in the twisted 6-s-cis conformation in rhodopsin, in contrast to the planar 6-s-trans confirmation found in bacteriorhodopsin. The /sup 13/C-14 isotropic shift and shift tensor principal values show that the Schiff base C=N bond is anti. Furthermore, the /sup 13/C-14 chemical shift (121.2 ppm) is within the range of values (120-123 ppm) exhibited by protonated (C=N anti) Schiff base model compounds, indicating that the C=N linkage is protonated. The results are discussed with regard to the mechanism of wavelength regulation in rhodopsin.

• Research Organization: Massachusetts Institute of Technology, Cambridge
• OSTI ID: 6469727
• Journal Information: Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 26:6; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
ANIMALS
BODY
BODY AREAS
CARBON 13
CARBON ISOTOPES
CATTLE
CHEMICAL SHIFT
DOMESTIC ANIMALS
EVEN-ODD NUCLEI
EYES
FACE
HEAD
IMINES
ISOTOPES
ISOTROPY
LIGHT NUCLEI
LOW TEMPERATURE
MAGNETIC RESONANCE
MAMMALS
NMR SPECTRA
NUCLEAR MAGNETIC RESONANCE
NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
PIGMENTS
PROTEINS
RESONANCE
RETINA
RHODOPSIN
RUMINANTS
SCHIFF BASES
SENSE ORGANS
SPECTRA
STABLE ISOTOPES
VERTEBRATES