Cryo-EM structure of the native rhodopsin dimer in nanodiscs
| Autor: | Oliver P. Ernst, Przemyslaw Miszta, Dorothy Yanling Zhao, Julia Mahamid, Takefumi Morizumi, Matthias Pöge, Slawomir Filipek, Sahil Gulati, Wolfgang Baumeister, Jianye Zhang, Ned Van Eps, Jürgen M. Plitzko, Krzysztof Palczewski |
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| Rok vydání: | 2019 |
| Předmět: |
0301 basic medicine
retina Opsin genetic structures receptor Dimer transducin Medical and Health Sciences Biochemistry chemistry.chemical_compound transmembrane helix 1 biology Chemistry Biological Sciences Transmembrane domain Rhodopsin Transducin Signal Transduction Biochemistry & Molecular Biology 1.1 Normal biological development and functioning cryo-electron microscopy Bioengineering retinoid-binding protein 03 medical and health sciences Protein Domains Underpinning research cell signaling Animals Humans G protein-coupled receptor Molecular Biology rhodopsin dimerization 030102 biochemistry & molecular biology Cryoelectron Microscopy Retinoid binding protein Neurosciences Cell Biology rod outer segment HEK293 Cells 030104 developmental biology Chemical Sciences Helix biology.protein Biophysics Nanoparticles double electron-electron resonance Cattle helix 8 sense organs Protein Multimerization |
| Zdroj: | J Biol Chem The Journal of biological chemistry, vol 294, iss 39 |
| ISSN: | 0021-9258 |
| Popis: | Imaging of rod photoreceptor outer-segment disc membranes by atomic force microscopy and cryo-electron tomography has revealed that the visual pigment rhodopsin, a prototypical class A G protein-coupled receptor (GPCR), can organize as rows of dimers. GPCR dimerization and oligomerization offer possibilities for allosteric regulation of GPCR activity, but the detailed structures and mechanism remain elusive. In this investigation, we made use of the high rhodopsin density in the native disc membranes and of a bifunctional cross-linker that preserves the native rhodopsin arrangement by covalently tethering rhodopsins via Lys residue side chains. We purified cross-linked rhodopsin dimers and reconstituted them into nanodiscs for cryo-EM analysis. We present cryo-EM structures of the cross-linked rhodopsin dimer as well as a rhodopsin dimer reconstituted into nanodiscs from purified monomers. We demonstrate the presence of a preferential 2-fold symmetrical dimerization interface mediated by transmembrane helix 1 and the cytoplasmic helix 8 of rhodopsin. We confirmed this dimer interface by double electron-electron resonance measurements of spin-labeled rhodopsin. We propose that this interface and the arrangement of two protomers is a prerequisite for the formation of the observed rows of dimers. We anticipate that the approach outlined here could be extended to other GPCRs or membrane receptors to better understand specific receptor dimerization mechanisms. |
| Databáze: | OpenAIRE |
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