3QEK:
reference: Subunit arrangement and phenylethanolamine binding in GluN1/GluN2B NMDA receptors., Karakas E, Simorowski N, Furukawa H, Nature. 2011 Jun 15;475(7355):249-53. doi: 10.1038/nature10180. PMID: 21677647

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