5T5A:
reference: The structure of a nucleolytic ribozyme that employs a catalytic metal ion., Liu Y, Wilson TJ, Lilley DM, Nat Chem Biol. 2017 Mar 6. doi: 10.1038/nchembio.2333. PMID: 28263963

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