6GDG:
reference: Cryo-EM structure of the adenosine A2A receptor coupled to an engineered heterotrimeric G protein., Garcia-Nafria J, Lee Y, Bai X, Carpenter B, Tate CG, Elife. 2018 May 4;7. pii: 35946. doi: 10.7554/eLife.35946. PMID: 29726815

This OCA Structure page
uses Jmol, developed by the Jmol Development Team (documentation).