3pb1
From Proteopedia
Crystal Structure of a Michaelis Complex between Plasminogen Activator Inhibitor-1 and Urokinase-type Plasminogen Activator
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. 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] Publication Abstract from PubMedPlasminogen activator inhibitor-1 (PAI-1), together with its physiological target urokinase-type plasminogen activator (uPA), plays a pivotal role in fibrinolysis, cell migration, and tissue remodeling and is currently recognized as being among the most extensively validated biological prognostic factors in several cancer types. PAI-1 specifically and rapidly inhibits uPA and tissue-type PA (tPA). Despite extensive structural/functional studies on these two reactions, the underlying structural mechanism has remained unknown due to the technical difficulties of obtaining the relevant structures. Here, we report a strategy to generate a PAI-1.uPA(S195A) Michaelis complex and present its crystal structure at 2.3-A resolution. In this structure, the PAI-1 reactive center loop serves as a bait to attract uPA onto the top of the PAI-1 molecule. The P4-P3' residues of the reactive center loop interact extensively with the uPA catalytic site, accounting for about two-thirds of the total contact area. Besides the active site, almost all uPA exosite loops, including the 37-, 60-, 97-, 147-, and 217-loops, are involved in the interaction with PAI-1. The uPA 37-loop makes an extensive interaction with PAI-1 beta-sheet B, and the 147-loop directly contacts PAI-1 beta-sheet C. Both loops are important for initial Michaelis complex formation. This study lays down a foundation for understanding the specificity of PAI-1 for uPA and tPA and provides a structural basis for further functional studies. Structural basis for recognition of urokinase-type plasminogen activator by plasminogen activator inhibitor-1.,Lin Z, Jiang L, Yuan C, Jensen JK, Zhang X, Luo Z, Furie BC, Furie B, Andreasen PA, Huang M J Biol Chem. 2011 Mar 4;286(9):7027-32. Epub 2011 Jan 3. PMID:21199867[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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