6DLR:
reference: ykkC riboswitches employ an add-on helix to adjust specificity for polyanionic ligands., Peselis A, Serganov A, Nat Chem Biol. 2018 Sep;14(9):887-894. doi: 10.1038/s41589-018-0114-4. Epub 2018 , Aug 17. PMID: 30120360

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