Small-Angle Neutron Scattering Reveals Energy Landscape for Rhodopsin Photoactivation

Suchithranga M.D.C. Perera, Udeep Chawla, Utsab R. Shrestha, Debsindhu Bhowmik, Andrey V. Struts, Shuo Qian, Xiang Qiang Chu, Michael F Brown

Research output: Contribution to journalArticle

2 Scopus citations

Abstract

Knowledge of the activation principles for G-protein-coupled receptors (GPCRs) is critical to development of new pharmaceuticals. Rhodopsin is the archetype for the largest GPCR family, yet the changes in protein dynamics that trigger signaling are not fully understood. Here we show that rhodopsin can be investigated by small-angle neutron scattering (SANS) in fully protiated detergent micelles under contrast matching to resolve light-induced changes in the protein structure. In SANS studies of membrane proteins, the zwitterionic detergent [(cholamidopropyl)dimethylammonio]-propanesulfonate (CHAPS) is advantageous because of the low contrast difference between the hydrophobic core and hydrophilic head groups as compared with alkyl glycoside detergents. Combining SANS results with quasielastic neutron scattering reveals how changes in volumetric protein shape are coupled (slaved) to the aqueous solvent. Upon light exposure, rhodopsin is swollen by the penetration of water into the protein core, allowing interactions with effector proteins in the visual signaling mechanism.

Original languageEnglish (US)
Pages (from-to)7064-7071
Number of pages8
JournalJournal of Physical Chemistry Letters
Volume9
Issue number24
DOIs
Publication statusPublished - Dec 20 2018

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ASJC Scopus subject areas

  • Materials Science(all)
  • Physical and Theoretical Chemistry

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