4GCW:
reference: Activation of tRNA Maturation by Downstream Uracil Residues in B. subtilis., Pellegrini O, Li de la Sierra-Gallay I, Piton J, Gilet L, Condon C, Structure. 2012 Oct 10;20(10):1769-77. doi: 10.1016/j.str.2012.08.002. Epub 2012 , Aug 30. PMID: 22940585

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