4NYA:
reference: Validating Fragment-Based Drug Discovery for Biological RNAs: Lead Fragments Bind and Remodel the TPP Riboswitch Specifically., Warner KD, Homan P, Weeks KM, Smith AG, Abell C, Ferre-D'Amare AR, Chem Biol. 2014 May 22;21(5):591-5. doi: 10.1016/j.chembiol.2014.03.007. Epub, 2014 Apr 24. PMID: 24768306

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