1RTC:
reference: Structure of recombinant ricin A chain at 2.3 A., Mlsna D, Monzingo AF, Katzin BJ, Ernst S, Robertus JD, Protein Sci 1993 Mar;2(3):429-35. PMID: 8453380

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