Accurate measurements of 13C-13C J-couplings in the rhodopsin chromophore by double-quantum solid-state NMR spectroscopy.
A new double-quantum solid-state NMR pulse sequence is presented and used to measure one-bond 13C-13C J-couplings in a set of 13C2-labeled rhodopsin isotopomers. The measured J-couplings reveal a perturbation of the electronic structure at the terminus of the conjugated chain but show no evidence for protein-induced electronic perturbation near the C11-C12 isomerization site. This work establishes NMR methodology for measuring accurate 1JCC values in noncrystalline macromolecules and shows that the measured J-couplings may reveal local electronic perturbations of mechanistic significance.
School of Chemistry, University of Southampton, SO17 1BJ Southampton, UK.
Wai Cheu
WC
Lai
Neville
N
McLean
Axel
A
Gansmüller
Michiel A
MA
Verhoeven
Gian Carlo
GC
Antonioli
Marina
M
Carravetta
Luminita
L
Duma
Petra H M
PH
Bovee-Geurts
Ole G
OG
Johannessen
Huub J M
HJ
de Groot
Johan
J
Lugtenburg
Lyndon
L
Emsley
Steven P
SP
Brown
Richard C D
RC
Brown
Willem J
WJ
DeGrip
Malcolm H
MH
Levitt
D002247:Carbon Isotopes; D007553:Isotope Labeling; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D011789:Quantum Theory; D012243:Rhodopsin / Q000737:chemistry*
D002247:Carbon Isotopes; D012243:Rhodopsin