1SNM:
reference: Active site mutant Glu-43----Asp in staphylococcal nuclease displays nonlocal structural changes., Loll PJ, Lattman EE, Biochemistry. 1990 Jul 24;29(29):6866-73. PMID: 2397218

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