Fibrin self-assembly interfaces

Fibrin self-assembly interfaces are the specific molecular contact points responsible for the polymerization of fibrin monomers into a stable, three-dimensional blood clot. This process is initiated when thrombin cleaves fibrinopeptides A and B from fibrinogen, exposing N-terminal "knobs" (A and B) that bind to complementary "holes" (a and b) located in the C-terminal domains of neighboring fibrin molecules (MedlinePlus, 2023; PubMed: 15153610). The A-a interaction is essential for the longitudinal growth of protofibrils, while the B-b interaction facilitates lateral aggregation and branching of the fibrin network (UniProt: P02671). Because these interfaces are the final structural step in clot formation, they represent a unique therapeutic target for anticoagulants designed to prevent thrombosis without broadly inhibiting the enzymatic cascade of coagulation (PubMed: 21844475). Experimental drugs, such as GPRP-based peptides, work by mimicking the knobs and occupying the holes, thereby blocking the assembly of the fibrin matrix (PubMed: 11586356). These interfaces are also critical in the context of wound healing and tissue engineering, where the mechanical properties of the fibrin scaffold are determined by the strength and density of these interactions.

Other names

Knob-hole interactionsFibrin polymerization sitesA-a and B-b interactionsFibrinogen-to-fibrin conversion sites

Competitive inhibition of knob-hole interactions to prevent fibrin polymerization.