CRYSTAL-STRUCTURES OF FRAGMENT-D FROM HUMAN FIBRINOGEN AND ITS CROSS-LINKED COUNTERPART FROM FIBRIN

In blood coagulation, units of the protein fibrinogen pack together to form a fibrin clot, but a crystal structure for fibrinogen is needed to understand how this is achieved. The structure of a cove fragment ( fragment D) from human fibrinogen has now been determined to 2.9 Angst rom resolution. The 86K three-chained structure consists of a coiled-c oil region and two homologous globular entities oriented at approximat ely 130 degrees to each other, Additionally, the covalently bound dime r of fragment D, known as 'doubte-D', was isolated from human fibrin, crystallized in the presence of a Gly-Pro-Arg-Pro-amide peptide ligand , which simulates the donor polymerization site, and its structure sol ved by molecular replacement with the model of fragment D.