5IKB:
reference: The Structure of a High-Affinity Kainate Receptor: GluK4 Ligand-Binding Domain Crystallized with Kainate., Kristensen O, Kristensen LB, Mollerud S, Frydenvang K, Pickering DS, Kastrup JS, Structure. 2016 Sep 6;24(9):1582-9. doi: 10.1016/j.str.2016.06.019. Epub 2016 Aug, 11. PMID: 27524200

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