3R3G:
reference: Rigidification of the autolysis loop enhances Na(+) binding to thrombin., Pozzi N, Chen R, Chen Z, Bah A, Di Cera E, Biophys Chem. 2011 Apr 12. PMID: 21536369

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