1V2X:
reference: Deep knot structure for construction of active site and cofactor binding site of tRNA modification enzyme., Nureki O, Watanabe K, Fukai S, Ishii R, Endo Y, Hori H, Yokoyama S, Structure (Camb) 2004 Apr;12(4):593-602. PMID: 15062082

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