Fibrinogen gamma chain D-domain hole a (Hole a) (Hole a)

The Fibrin D-domain "hole a" is a specialized binding pocket located in the gamma-nodule of the fibrinogen molecule, specifically within the C-terminal region of the gamma chain (UniProt P02679). It is a fundamental component of the "knob-hole" interaction mechanism essential for blood coagulation (PubMed: 10430871). Following the thrombin-mediated removal of fibrinopeptide A from the N-terminus of the fibrinogen alpha-chain, a new N-terminus (knob A) is exposed, which then fits into "hole a" of an adjacent fibrin molecule (PubMed: 11133187). This specific molecular recognition facilitates the ordered assembly of fibrin monomers into half-staggered, double-stranded protofibrils, forming the structural scaffold of a blood clot (PubMed: 22493297). In the context of disease, dysregulation of this process contributes to pathological thrombosis, including myocardial infarction and stroke. Consequently, "hole a" serves as a target for antithrombotic drug development, where synthetic peptides or small molecules mimicking the "knob A" sequence (such as Gly-Pro-Arg-Pro) are used to competitively occupy the pocket and inhibit fibrin polymerization.

Other names

gamma-chain holehole "a"D-domain pocket agamma-nodule hole

Competitive inhibition of the knob-hole interaction between fibrin monomers to prevent protofibril formation and clot stabilization.