Report

Structural Basis for Allosteric Regulation of GPCRs by Sodium Ions

Science  13 Jul 2012:
Vol. 337, Issue 6091, pp. 232-236
DOI: 10.1126/science.1219218

You are currently viewing the abstract.

View Full Text
As a service to the community, AAAS/Science has made this article free with registration.

Abstract

Pharmacological responses of G protein–coupled receptors (GPCRs) can be fine-tuned by allosteric modulators. Structural studies of such effects have been limited due to the medium resolution of GPCR structures. We reengineered the human A2A adenosine receptor by replacing its third intracellular loop with apocytochrome b562RIL and solved the structure at 1.8 angstrom resolution. The high-resolution structure allowed us to identify 57 ordered water molecules inside the receptor comprising three major clusters. The central cluster harbors a putative sodium ion bound to the highly conserved aspartate residue Asp2.50. Additionally, two cholesterols stabilize the conformation of helix VI, and one of 23 ordered lipids intercalates inside the ligand-binding pocket. These high-resolution details shed light on the potential role of structured water molecules, sodium ions, and lipids/cholesterol in GPCR stabilization and function.

View Full Text

Cited By...