(A) Schemata of fibrinogen and fibrin molecules. D:D: structure on each D region that interfaces with its counterpart on another molecule. αC: carboxyl terminal region of the Aα chain. Coiled coil: interior parts of each chain connecting E and D regions. FpA and FpB: fibrinopeptides A and B, respectively. “a” and “b” pockets: complementary binding sites for “A” and “B” knobs, respectively (bottom schemata). Des-AA and Des-AA/DesBB fibrin: fibrin lacking its FpAs or both its FpAs and FpBs. (B) Molecular composition of some of the fibrin structures observed by Chernysh and colleages. (C) Possible composition of some fibrin oligomers in fibrin/fibrinogen complexes showing that incorporation of fibrinogen interrupts elongation. Fibrinogen E/fibrin D juxtaposition is consistent with fibrinogen self-assembly data.9 Professional illustration by Alice Y. Chen.
