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Coupling of retinal isomerization to the activation of rhodopsin

Coupling of retinal isomerization to the activation of rhodopsin Activation of the visual pigment rhodopsin is caused by 11-cis to -trans isomerization of its retinal chromophore. High-resolution solid-state NMR measurements on both rhodopsin and the metarhodopsin II intermediate show how retinal isomerization disrupts helix interactions that lock the receptor off in the dark. We made 2D dipolar-assisted rotational resonance NMR measurements between 13C-labels on the retinal chromophore and specific 13C-labels on tyrosine, glycine, serine, and threonine in the retinal binding site of rhodopsin. The essential aspects of the isomerization trajectory are a large rotation of the C20 methyl group toward extracellular loop 2 and a 4- to 5-Å translation of the retinal chromophore toward transmembrane helix 5. The retinal–protein contacts observed in the active metarhodopsin II intermediate suggest a general activation mechanism for class A G protein-coupled receptors involving coupled motion of transmembrane helices 5, 6, and 7. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Proceedings of the National Academy of Sciences PNAS

Coupling of retinal isomerization to the activation of rhodopsin

Coupling of retinal isomerization to the activation of rhodopsin

Proceedings of the National Academy of Sciences , Volume 101 (27): 10048 – Jul 6, 2004

Abstract

Activation of the visual pigment rhodopsin is caused by 11-cis to -trans isomerization of its retinal chromophore. High-resolution solid-state NMR measurements on both rhodopsin and the metarhodopsin II intermediate show how retinal isomerization disrupts helix interactions that lock the receptor off in the dark. We made 2D dipolar-assisted rotational resonance NMR measurements between 13C-labels on the retinal chromophore and specific 13C-labels on tyrosine, glycine, serine, and threonine in the retinal binding site of rhodopsin. The essential aspects of the isomerization trajectory are a large rotation of the C20 methyl group toward extracellular loop 2 and a 4- to 5-Å translation of the retinal chromophore toward transmembrane helix 5. The retinal–protein contacts observed in the active metarhodopsin II intermediate suggest a general activation mechanism for class A G protein-coupled receptors involving coupled motion of transmembrane helices 5, 6, and 7.

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Publisher
PNAS
Copyright
Copyright ©2009 by the National Academy of Sciences
ISSN
0027-8424
eISSN
1091-6490
Publisher site
See Article on Publisher Site

Abstract

Activation of the visual pigment rhodopsin is caused by 11-cis to -trans isomerization of its retinal chromophore. High-resolution solid-state NMR measurements on both rhodopsin and the metarhodopsin II intermediate show how retinal isomerization disrupts helix interactions that lock the receptor off in the dark. We made 2D dipolar-assisted rotational resonance NMR measurements between 13C-labels on the retinal chromophore and specific 13C-labels on tyrosine, glycine, serine, and threonine in the retinal binding site of rhodopsin. The essential aspects of the isomerization trajectory are a large rotation of the C20 methyl group toward extracellular loop 2 and a 4- to 5-Å translation of the retinal chromophore toward transmembrane helix 5. The retinal–protein contacts observed in the active metarhodopsin II intermediate suggest a general activation mechanism for class A G protein-coupled receptors involving coupled motion of transmembrane helices 5, 6, and 7.

Journal

Proceedings of the National Academy of SciencesPNAS

Published: Jul 6, 2004

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