5EAO:
reference: Two Active Site Divalent Ions in the Crystal Structure of the Hammerhead Ribozyme Bound to a Transition State Analogue., Mir A, Golden BL, Biochemistry. 2016 Feb 2;55(4):633-6. doi: 10.1021/acs.biochem.5b01139. Epub 2016, Jan 19. PMID: 26551631

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