View source for 4x1q


==The crystal structure of mupain-1 in complex with murinised human uPA at pH7.4==
<StructureSection load='4x1q' size='340' side='right'caption='[[4x1q]], [[Resolution|resolution]] 2.28&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4x1q]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] and [https://en.wikipedia.org/wiki/Synthetic_construct Synthetic construct]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4X1Q OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4X1Q FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.28&#8491;</td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=4x1q FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4x1q OCA], [https://pdbe.org/4x1q PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4x1q RCSB], [https://www.ebi.ac.uk/pdbsum/4x1q PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4x1q ProSAT]</span></td></tr>
</table>
== Disease ==
[https://www.uniprot.org/uniprot/UROK_HUMAN UROK_HUMAN] Defects in PLAU are the cause of Quebec platelet disorder (QPD) [MIM:[https://omim.org/entry/601709 601709]. QPD is an autosomal dominant bleeding disorder due to a gain-of-function defect in fibrinolysis. Although affected individuals do not exhibit systemic fibrinolysis, they show delayed onset bleeding after challenge, such as surgery. The hallmark of the disorder is markedly increased PLAU levels within platelets, which causes intraplatelet plasmin generation and secondary degradation of alpha-granule proteins.<ref>PMID:20007542</ref> 
== Function ==
[https://www.uniprot.org/uniprot/UROK_HUMAN UROK_HUMAN] Specifically cleaves the zymogen plasminogen to form the active enzyme plasmin.
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Peptides are attracting increasing interest as protease inhibitors. Here, we demonstrate a new inhibitory mechanism and a new type of exosite interactions for a phage-displayed peptide library-derived competitive inhibitor, mupain-1 (CPAYSRYLDC), of the serine protease murine urokinase-type plasminogen activator (uPA). We used X-ray crystal structure analysis, site-directed mutagenesis, liquid state NMR, surface plasmon resonance analysis, and isothermal titration calorimetry and wild type and engineered variants of murine and human uPA. We demonstrate that Arg6 inserts into the S1 specificity pocket, its carbonyl group aligning improperly relative to Ser195 and the oxyanion hole, explaining why the peptide is an inhibitor rather than a substrate. Substitution of the P1 Arg with novel unnatural Arg analogues with aliphatic or aromatic ring structures led to an increased affinity, depending on changes in both P1 - S1 and exosite interactions. Site-directed mutagenesis showed that exosite interactions, while still supporting high affinity binding, differed substantially between different uPA variants. Surprisingly, high affinity binding was facilitated by Ala-substitution of Asp9 of the peptide, in spite of a less favorable binding entropy and loss of a polar interaction. We conclude that increased flexibility of the peptide allows more favorable exosite interactions, which, in combination with the use of novel Arg analogues as P1 residues, can be used to manipulate the affinity and specificity of this peptidic inhibitor, a concept different from conventional attempts at improving inhibitor affinity by reducing the entropic burden.

A cyclic peptidic serine protease inhibitor: increasing affinity by increasing peptide flexibility.,Zhao B, Xu P, Jiang L, Paaske B, Kromann-Hansen T, Jensen JK, Sorensen HP, Liu Z, Nielsen JT, Christensen A, Hosseini M, Sorensen KK, Nielsen NC, Jensen KJ, Huang M, Andreasen PA PLoS One. 2014 Dec 29;9(12):e115872. doi: 10.1371/journal.pone.0115872., eCollection 2014. PMID:25545505<ref>PMID:25545505</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 4x1q" style="background-color:#fffaf0;"></div>

==See Also==
*[[Plasminogen activator|Plasminogen activator]]
*[[Urokinase 3D Structures|Urokinase 3D Structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Synthetic construct]]
[[Category: Andreasen P]]
[[Category: Huang M]]
[[Category: Jiang L]]
[[Category: Xu P]]
[[Category: Zhao B]]