6BJR:
reference: Structure of prothrombin in the closed form reveals new details on the mechanism of activation., Chinnaraj M, Chen Z, Pelc LA, Grese Z, Bystranowska D, Di Cera E, Pozzi N, Sci Rep. 2018 Feb 13;8(1):2945. doi: 10.1038/s41598-018-21304-1. PMID: 29440720

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