Slow conformational dynamics of the human A2A adenosine receptor are temporally ordered

Shushu Wei; Naveen Thakur; Arka P Ray; Beining Jin; Samuel Obeng; Christopher R McCurdy; Lance R McMahon; Hugo Gutiérrez-de-Terán; Matthew T Eddy; Rajan Lamichhane

doi:10.1016/j.str.2021.11.005

Slow conformational dynamics of the human A_2A adenosine receptor are temporally ordered

Structure. 2022 Mar 3;30(3):329-337.e5. doi: 10.1016/j.str.2021.11.005. Epub 2021 Dec 10.

Authors

Affiliations

¹ Department of Biochemistry & Cellular and Molecular Biology, College of Arts and Sciences, University of Tennessee, 1311 Cumberland Avenue, Knoxville, TN 37932, USA.
² Department of Chemistry, College of Liberal Arts and Sciences, University of Florida, 126 Sisler Hall, Gainesville, FL 32611, USA.
³ Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL 32610, USA; Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, FL 32610, USA.
⁴ Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, FL 32610, USA; Translational Drug Development Core, Clinical and Translational Sciences Institute, University of Florida, Gainesville, FL 32610, USA.
⁵ Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL 32610, USA.
⁶ Department of Cell and Molecular Biology, Uppsala University, B.M.C., Box 596, Uppsala 751 24, Sweden.
⁷ Department of Chemistry, College of Liberal Arts and Sciences, University of Florida, 126 Sisler Hall, Gainesville, FL 32611, USA. Electronic address: matthew.eddy@chem.ufl.edu.
⁸ Department of Biochemistry & Cellular and Molecular Biology, College of Arts and Sciences, University of Tennessee, 1311 Cumberland Avenue, Knoxville, TN 37932, USA. Electronic address: rajan@utk.edu.

Abstract

A more complete depiction of protein energy landscapes includes the identification of different function-related conformational states and the determination of the pathways connecting them. We used total internal reflection fluorescence (TIRF) imaging to investigate the conformational dynamics of the human A_2A adenosine receptor (A_2AAR), a class A G protein-coupled receptor (GPCR), at the single-molecule level. Slow, reversible conformational exchange was observed among three different fluorescence emission states populated for agonist-bound A_2AAR. Transitions among these states predominantly occurred in a specific order, and exchange between inactive and active-like conformations proceeded through an intermediate state. Models derived from molecular dynamics simulations with available A_2AAR structures rationalized the relative fluorescence emission intensities for the highest and lowest emission states but not the transition state. This suggests that the functionally critical intermediate state required to achieve activation is not currently visualized among available A_2AAR structures.

Keywords: A2A adenosine receptor; G-protein-coupled receptors; TIRF; biophysics; conformational dynamics; lipid nanodiscs; membrane proteins; single-molecule fluorescence spectroscopy.

Publication types

Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

MeSH terms

Humans
Molecular Conformation
Molecular Dynamics Simulation*
Receptor, Adenosine A2A* / chemistry

Substances

Receptor, Adenosine A2A

Abstract

Publication types

MeSH terms

Substances

Grants and funding