4XBF:
reference: G-quadruplex RNA binding and recognition by the lysine-specific histone demethylase-1 enzyme., Hirschi A, Martin WJ, Luka Z, Loukachevitch LV, Reiter NJ, RNA. 2016 Aug;22(8):1250-60. doi: 10.1261/rna.057265.116. Epub 2016 Jun 8. PMID: 27277658

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