Measurement of dipolar couplings in a transducin peptide fragment weakly bound to oriented photo-activated rhodopsin |
| |
Authors: | Bernd W. Koenig Drake C. Mitchell Simone König Stephan Grzesiek Burton J. Litman Ad Bax |
| |
Affiliation: | (1) Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Bethesda, MD, 20892-0520, U.S.A.;(2) Laboratory of Membrane Biophysics and Biochemistry, NIAAA, National Institutes of Health, Rockville;(3) Laboratory of Biophysical Chemistry, NHLBI, National Institutes of Health, Bethesda, MD, 20892, U.S.A.;(4) Structural Biology Institute, Research Center Jülich, D-52425 Jülich, Germany |
| |
Abstract: | Rhodopsin-containing disks, isolated from rod outer segments of bovine retina, align at high magnetic fields with their membrane normal parallel to the magnetic field. After light-activation of rhodopsin, transient binding of the C-terminal transducin undecapeptide, selectively labeled with 15N at Leu5 and Gly9, results in residual dipolar contributions to the 1JNH splittings for these two residues. Both residues show 1JNH splittings which are smaller than in the dark-adapted or rhodopsin-free sample, and return to their isotropic values at a rate determined by the decay of the meta II state of rhodopsin. The dipolar couplings indicate that in the bound state, N-H vectors of Leu5 and Gly9 make angles of 48±4° and 40±8°, respectively, with the disk normal. These `transferred' dipolar couplings potentially offer a useful method for studying the conformation and orientation of flexible, low affinity ligands when bound to oriented integral membrane receptors. |
| |
Keywords: | alignment membrane protein receptor rhodopsin transferred dipolar coupling transducin |
本文献已被 PubMed SpringerLink 等数据库收录! |
|