1KAJ:
reference: Conformation of a non-frameshifting RNA pseudoknot from mouse mammary tumor virus., Kang H, Hines JV, Tinoco I Jr, J Mol Biol 1996 May 31;259(1):135-47. PMID: 8648641

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