1XMN:
reference: Crystal structure of thrombin bound to heparin., Carter WJ, Cama E, Huntington JA, J Biol Chem 2005 Jan 28;280(4):2745-9. Epub 2004 Nov 17. PMID: 15548541

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