6GH0:
reference: Two-quartet kit* G-quadruplex is formed via double-stranded pre-folded structure., Kotar A, Rigo R, Sissi C, Plavec J, Nucleic Acids Res. 2018 Dec 21. pii: 5257350. doi: 10.1093/nar/gky1269. PMID: 30590801

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