Plasminogen lysine-binding domains (PLG LBDs) (PLG LBDs)

Plasminogen lysine-binding domains (LBDs) are specialized structural motifs, primarily found within the five kringle domains of the plasminogen protein, that play a pivotal role in the regulation of the fibrinolytic system (Source: UniProt P00747). These domains specifically recognize and bind to C-terminal lysine residues on fibrin clots and various cell surface receptors, effectively localizing plasminogen to sites of fibrin deposition or cellular activity (Source: PubMed PMID: 12169745). This binding is a prerequisite for the efficient conversion of the zymogen plasminogen into the active serine protease plasmin by activators such as tissue-type plasminogen activator (tPA). In therapeutic contexts, LBDs are the molecular targets for antifibrinolytic agents like tranexamic acid and aminocaproic acid, which mimic lysine and competitively inhibit the binding of plasminogen to fibrin, thus stabilizing clots and reducing bleeding (Source: StatPearls, PMID: 30725604). Additionally, certain LBD-containing fragments, such as angiostatin, have been identified as endogenous inhibitors of angiogenesis, highlighting their importance in oncology and vascular biology (Source: PubMed PMID: 7526331). The LBDs also facilitate plasminogen's interaction with bacterial proteins, which can contribute to the invasiveness of certain pathogens (Source: PubMed PMID: 11591459).

Other names

Kringle domainsLysine-binding sitesLBSPlasminogen kringlesPLG Kringles

Competitive inhibition of lysine binding to prevent the association of plasminogen and plasmin with fibrin and cell surfaces, thereby inhibiting fibrinolysis (Source: StatPearls, PMID: 30725604).