1DDD:
reference: Modelling the P2Y purinoceptor using rhodopsin as template., Van Rhee AM, Fischer B, Van Galen PJ, Jacobson KA, Drug Des Discov 1995 Nov;13(2):133-54. PMID: 8872457

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