5brr
From Proteopedia
Michaelis complex of tPA-S195A:PAI-1
Structural highlights
Disease[PAI1_HUMAN] Defects in SERPINE1 are the cause of plasminogen activator inhibitor-1 deficiency (PAI-1D) [MIM:613329]. It is a hematologic disorder characterized by increased bleeding after trauma, injury, or surgery. Affected females have menorrhagia. The bleeding defect is due to increased fibrinolysis of fibrin blood clots due to deficiency of plasminogen activator inhibitor-1, which inhibits tissue and urinary activators of plasminogen.[1] Note=High concentrations of SERPINE1 seem to contribute to the development of venous but not arterial occlusions. [TPA_HUMAN] Note=Increased activity of TPA results in increased fibrinolysis of fibrin blood clots that is associated with excessive bleeding. Defective release of TPA results in hypofibrinolysis that can lead to thrombosis or embolism. Function[PAI1_HUMAN] Serine protease inhibitor. This inhibitor acts as 'bait' for tissue plasminogen activator, urokinase, protein C and matriptase-3/TMPRSS7. Its rapid interaction with PLAT may function as a major control point in the regulation of fibrinolysis.[2] [TPA_HUMAN] Converts the abundant, but inactive, zymogen plasminogen to plasmin by hydrolyzing a single Arg-Val bond in plasminogen. By controlling plasmin-mediated proteolysis, it plays an important role in tissue remodeling and degradation, in cell migration and many other physiopathological events. Plays a direct role in facilitating neuronal migration. Publication Abstract from PubMedThrombosis is a leading cause of death worldwide. Recombinant tissue-type plasminogen activator (tPA) is the FDA-approved thrombolytic drug. tPA is rapidly inactivated by endogenous plasminogen activators inhibitor-1 (PAI-1). Engineering on tPA to reduce its inhibition by PAI-1 without compromising its thrombolytic effect is a continuous effort. Precise details, with atomic resolution, of the molecular interactions between tPA and PAI-1 remains unknown despite extensive previous studies. Here, we report the crystal structure of tPA.PAI-1 Michaelis complex, which shows significant differences from the structure of its urokinase-type plasminogen activator (uPA) analogue, the uPA.PAI-1 Michaelis complex. The PAI-1 reactive center loop (RCL) adopts a unique kinked conformation, and the first 5 residues of RCL bends toward the beta-sheet A. The structure provides detailed interactions between tPA 37- and 60-loops with PAI-1. On the tPA side, the S2 and S1beta pockets opens up to accommodate PAI-1. This study lays down a foundation for understanding the specificity of PAI-1 for tPA, and provides structural clues to design newer generation of thrombolytic agents with reduced PAI-1 inactivation. Crystal Structure of the Michaelis Complex between Tissue-type Plasminogen Activator and Plasminogen Activators Inhibitor-1.,Gong L, Liu M, Zeng T, Shi X, Yuan C, Andreasen PA, Huang M J Biol Chem. 2015 Aug 31. pii: jbc.M115.677567. PMID:26324706[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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