3HTC:
reference: The structure of a complex of recombinant hirudin and human alpha-thrombin., Rydel TJ, Ravichandran KG, Tulinsky A, Bode W, Huber R, Roitsch C, Fenton JW 2nd, Science 1990 Jul 20;249(4966):277-80. PMID: 2374926

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