3RKF:
reference: Influence of ground-state structure and Mg2+ binding on folding kinetics of the guanine-sensing riboswitch aptamer domain., Buck J, Wacker A, Warkentin E, Wohnert J, Wirmer-Bartoschek J, Schwalbe H, Nucleic Acids Res. 2011 Sep 2. PMID: 21890900

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