Structural highlights
FunctionAA2AR_HUMAN Receptor for adenosine. The activity of this receptor is mediated by G proteins which activate adenylyl cyclase.C562_ECOLX Electron-transport protein of unknown function. Publication Abstract from PubMedG protein-coupled receptors (GPCRs), or seven-transmembrane receptors, are a superfamily of membrane proteins that are critically important to physiological processes in the human body. Determining high-resolution structures of GPCRs without bound cognate signaling partners, such as a G protein, requires crystallization in lipidic cubic phase (LCP). GPCR crystals grown in LCP are often too small for traditional X-ray crystallography. These microcrystals are ideal for investigation by microcrystal electron diffraction (MicroED), but the gel-like nature of LCP makes traditional approaches to MicroED sample preparation insurmountable. Here, we show that the structure of a human A2A adenosine receptor can be determined by MicroED after converting the LCP into the sponge phase followed by focused ion-beam milling. We determined the structure of the A2A adenosine receptor to 2.8-A resolution and resolved an antagonist in its orthosteric ligand-binding site, as well as four cholesterol molecules bound around the receptor. This study lays the groundwork for future structural studies of lipid-embedded membrane proteins by MicroED using single microcrystals that would be impossible with other crystallographic methods. MicroED structure of the human adenosine receptor determined from a single nanocrystal in LCP.,Martynowycz MW, Shiriaeva A, Ge X, Hattne J, Nannenga BL, Cherezov V, Gonen T Proc Natl Acad Sci U S A. 2021 Sep 7;118(36). pii: 2106041118. doi:, 10.1073/pnas.2106041118. PMID:34462357[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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