3JZ1:
reference: Mutant N143P reveals how Na+ activates thrombin., Niu W, Chen Z, Bush-Pelc LA, Bah A, Gandhi PS, Di Cera E, J Biol Chem. 2009 Dec 25;284(52):36175-85. Epub 2009 Oct 21. PMID: 19846563

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