Fibrinogen is a protein involved in platelet aggregation and is essential for the coagulation of blood. This domain forms part of the central coiled coiled region of the protein which is formed from two sets of three non-identical chains (alpha, beta and gamma).

1: Crystal structure of native chicken fibrinogen at 2.7 A resolution. Yang Z, Kollman JM, Pandi L, Doolittle RF; Biochemistry. 2001;40:12515-12523. PMID:11601975