2RNS:
reference: Refinement of the crystal structure of ribonuclease S. Comparison with and between the various ribonuclease A structures., Kim EE, Varadarajan R, Wyckoff HW, Richards FM, Biochemistry 1992 Dec 15;31(49):12304-14. PMID: 1463719

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