Schematic representation of the fibrinogen molecule.

Fibrinogen consists of 6 polypeptide chains held together by disulfide bonds in a molecule with bilateral symmetry. Illustrated in the Figure are the central region (E), which contains the fibrinopeptides; the distal region (D); α-helical coiled-coil segments parts of which are included in both the D and E regions; αC-domain; and the γ′ segment, which contains a thrombin and factor XIII binding site.