4Z7K:
reference: A Non-Stem-Loop CRISPR RNA Is Processed by Dual Binding Cas6., Shao Y, Richter H, Sun S, Sharma K, Urlaub H, Randau L, Li H, Structure. 2016 Apr 5;24(4):547-554. doi: 10.1016/j.str.2016.02.009. Epub 2016, Mar 17. PMID: 26996962

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