Fibrin–fibrin protein–protein interfaces

Fibrin–fibrin protein–protein interfaces are the structural contact points essential for the polymerization of fibrin monomers into a stable blood clot (Weisel & Litvinov, 2017). This process is initiated when thrombin cleaves fibrinopeptides A and B from fibrinogen, exposing N-terminal "knobs" that bind to complementary "holes" in the C-terminal domains of neighboring fibrin molecules (Lord, 2007). These interactions, primarily the A-a and B-b knob-hole bonds, facilitate the longitudinal and lateral assembly of protofibrils into a dense meshwork (Litvinov et al., 2005). As a therapeutic target, disrupting these interfaces offers a strategy to prevent thrombosis without necessarily inhibiting the enzymatic activity of thrombin or other coagulation factors. Research into small-molecule inhibitors and mimetic peptides, such as Gly-Pro-Arg-Pro (GPRP), aims to develop anticoagulants that competitively occupy these holes, potentially offering a lower risk of bleeding compared to traditional systemic anticoagulants (PubMed: 15855166). These interfaces are also critical in the context of fibrinolysis, where the accessibility of the fibrin structure determines the efficacy of plasmin-mediated clot degradation.

Other names

Fibrin polymerization sitesKnob-hole interactionsA-a and B-b interfacesFibrin protofibril assembly sites

Competitive inhibition of N-terminal knob binding to C-terminal holes, preventing the longitudinal and lateral assembly of fibrin protofibrils.