5ugd
Protease InhibitorProtease Inhibitor
Structural highlights
DiseasePLMN_HUMAN Defects in PLG are the cause of plasminogen deficiency (PLGD) [MIM:217090. PLGD is characterized by decreased serum plasminogen activity. Two forms of the disorder are distinguished: type 1 deficiency is additionally characterized by decreased plasminogen antigen levels and clinical symptoms, whereas type 2 deficiency, also known as dysplasminogenemia, is characterized by normal, or slightly reduced antigen levels, and absence of clinical manifestations. Plasminogen deficiency type 1 results in markedly impaired extracellular fibrinolysis and chronic mucosal pseudomembranous lesions due to subepithelial fibrin deposition and inflammation. The most common clinical manifestation of type 1 deficiency is ligneous conjunctivitis in which pseudomembranes formation on the palpebral surfaces of the eye progresses to white, yellow-white, or red thick masses with a wood-like consistency that replace the normal mucosa.[1] [2] [3] [4] [5] [6] [7] [8] FunctionPLMN_HUMAN Plasmin dissolves the fibrin of blood clots and acts as a proteolytic factor in a variety of other processes including embryonic development, tissue remodeling, tumor invasion, and inflammation. In ovulation, weakens the walls of the Graafian follicle. It activates the urokinase-type plasminogen activator, collagenases and several complement zymogens, such as C1 and C5. Cleavage of fibronectin and laminin leads to cell detachment and apoptosis. Also cleaves fibrin, thrombospondin and von Willebrand factor. Its role in tissue remodeling and tumor invasion may be modulated by CSPG4. Binds to cells.[9] Angiostatin is an angiogenesis inhibitor that blocks neovascularization and growth of experimental primary and metastatic tumors in vivo.[10] Publication Abstract from PubMedThe zymogen protease plasminogen and its active form plasmin perform key roles in blood clot dissolution, tissue remodeling, cell migration, and bacterial pathogenesis. Dysregulation of the plasminogen/plasmin system results in life-threatening hemorrhagic disorders or thrombotic vascular occlusion. Accordingly, inhibitors of this system are clinically important. Currently, tranexamic acid (TXA), a molecule that prevents plasminogen activation through blocking recruitment to target substrates, is the most widely used inhibitor for the plasminogen/plasmin system in therapeutics. However, TXA lacks efficacy on the active form of plasmin. Thus, there is a need to develop specific inhibitors that target the protease active site. Here we report the crystal structures of plasmin in complex with the novel YO (trans-4-aminomethylcyclohexanecarbonyl-l-tyrosine-n-octylamide) class of small molecule inhibitors. We found that these inhibitors form key interactions with the S1 and S3' subsites of the catalytic cleft. Here, the TXA moiety of the YO compounds inserts into the primary (S1) specificity pocket, suggesting that TXA itself may function as a weak plasmin inhibitor, a hypothesis supported by subsequent biochemical and biophysical analyses. Mutational studies reveal that F587 of the S' subsite plays a key role in mediating the inhibitor interaction. Taken together, these data provide a foundation for the future development of small molecule inhibitors to specifically regulate plasmin function in a range of diseases and disorders. X-ray crystal structure of plasmin with tranexamic acid-derived active site inhibitors.,Law RHP, Wu G, Leung EWW, Hidaka K, Quek AJ, Caradoc-Davies TT, Jeevarajah D, Conroy PJ, Kirby NM, Norton RS, Tsuda Y, Whisstock JC Blood Adv. 2017 May 9;1(12):766-771. doi: 10.1182/bloodadvances.2016004150., eCollection 2017 May 9. PMID:29296720[11] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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