5UIG:
reference: Crystal structure of the adenosine A2A receptor bound to an antagonist reveals a potential allosteric pocket., Sun B, Bachhawat P, Chu ML, Wood M, Ceska T, Sands ZA, Mercier J, Lebon F, Kobilka TS, Kobilka BK, Proc Natl Acad Sci U S A. 2017 Feb 21;114(8):2066-2071. doi:, 10.1073/pnas.1621423114. Epub 2017 Feb 6. PMID: 28167788

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