View source for 6har


==Crystal structure of Mesotrypsin in complex with APPI-M17C/I18F/F34C==
<StructureSection load='6har' size='340' side='right'caption='[[6har]], [[Resolution|resolution]] 1.50&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6har]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6HAR OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6HAR 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]] 1.497&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=EDO:1,2-ETHANEDIOL'>EDO</scene></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=6har FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6har OCA], [https://pdbe.org/6har PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6har RCSB], [https://www.ebi.ac.uk/pdbsum/6har PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6har ProSAT]</span></td></tr>
</table>
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== Publication Abstract from PubMed ==
Serine protease inhibitors of the Kunitz-bovine pancreatic trypsin inhibitor (BPTI) family are ubiquitous biological regulators of proteolysis. These small proteins are resistant to proteolysis, but can be slowly cleaved within the protease binding loop by target proteases, thereby compromising their activity. For the human protease, mesotrypsin, this cleavage is especially rapid. Here, we aimed to stabilize the Kunitz domain structure against proteolysis through disulfide engineering. Substitution within the Kunitz inhibitor domain of the amyloid precursor protein (APPI) that incorporated a new disulfide bond between residues 17 and 34 reduced proteolysis by mesotrypsin 54-fold. Similar disulfide engineering of tissue factor pathway inhibitor-1 Kunitz domain 1 (KD1TFPI1) and bikunin Kunitz domain 2 (KD2bikunin) likewise stabilized these inhibitors against mesotrypsin proteolysis 17-fold and 6.6-fold, respectively. Crystal structures of disulfide-engineered APPI and KD1TFPI1 variants in a complex with mesotrypsin at 1.5 A and 2.0 A resolution, respectively, confirmed the formation of well-ordered disulfide bonds positioned to stabilize the binding loop. Long all-atom molecular dynamics simulations of disulfide-engineered Kunitz domains and their complexes with mesotrypsin revealed conformational stabilization of the primed side of the inhibitor binding loop by the engineered disulfide, along with global suppression of conformational dynamics in the Kunitz domain. Our findings suggest that the Cys17-Cys34 disulfide slows proteolysis by dampening conformational fluctuations in the binding loop and minimizing motion at the enzyme-inhibitor interface. The generalizable approach developed here for the stabilization against proteolysis of Kunitz domains, which can serve as important scaffolds for therapeutics, may thus find applications in drug development.

Disulfide engineering of human Kunitz-type serine protease inhibitors enhances proteolytic stability and target affinity toward mesotrypsin.,Cohen I, Coban M, Shahar A, Sankaran B, Hockla A, Lacham S, Caulfield TR, Radisky ES, Papo N J Biol Chem. 2019 Jan 30. pii: RA118.007292. doi: 10.1074/jbc.RA118.007292. PMID:30700553<ref>PMID:30700553</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Cohen I]]
[[Category: Papo N]]
[[Category: Radisky E]]
[[Category: Shahar A]]