Conformational quiescence of ADAMTS-13 prevents proteolytic promiscuity.

摘要: Essentials Recently, ADAMTS-13 has been shown to undergo substrate induced conformation activation. Conformational quiescence of may serve prevent off-target proteolysis in plasma. Conformationally active variants are capable proteolysing the Aα chain fibrinogen. This should be considered as developed potential therapeutic agents. Click hear Dr Zheng's presentation on structure function and cofactor-dependent regulation SUMMARY: Background Recent work revealed that circulates a 'closed' conformation, only fully interacting with von Willebrand factor (VWF) following conformational change. We hypothesized this also maintains specificity 'open' protease might facilitate proteolytic promiscuity. Objectives To identify novel for constitutively gain (GoF) variant (R568K/F592Y/R660K/Y661F/Y665F). Methods Fibrinogen was characterized using SDS PAGE liquid chromatography-tandem mass spectrometry (LC-MS/MS). Fibrin formation monitored by turbidity measurements fibrin visualized confocal microscopy. Results exhibits activity against human fibrinogen, but is manifest its Accordingly, GoF truncated such MDTCS exhibit activity. The cleavage site determined LC-MS/MS Lys225-Met226. Proteolysis fibrinogen impairs plasma-based assays, alters clot increases permeability. Although does not appear proteolyse preformed cross-linked fibrin, susceptibility tissue-type plasminogen activator (t-PA)-induced lysis plasmin clearance rate more than 8-fold compared wild-type (WT) (EC50 values 3.0 ± 1.7 nm 25.2 9.7 nm, respectively) vitro thrombosis models. Conclusion restricts protects fibrinogenolysis. Induced promiscuity will important agents thrombotic thrombocytopenic purpura (TTP) other cardiovascular diseases.