View source for 7a9k


==Co-substituted Keggin silicotungstate with covalent bond to proteinase K==
<StructureSection load='7a9k' size='340' side='right'caption='[[7a9k]], [[Resolution|resolution]] 1.62&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[7a9k]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Parengyodontium_album Parengyodontium album]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7A9K OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7A9K 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]] 1.62&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=R5Q:Co-substituted+Keggin+silicotungstate'>R5Q</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</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=7a9k FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7a9k OCA], [https://pdbe.org/7a9k PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7a9k RCSB], [https://www.ebi.ac.uk/pdbsum/7a9k PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7a9k ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/PRTK_PARAQ PRTK_PARAQ] Hydrolyzes keratin at aromatic and hydrophobic residues.
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
We report on the synthesis of the tetrasubstituted sandwich-type Keggin silicotungstates as the pure Na salts Na14[(A-alpha-SiW10O37)2{Co4(OH)2(H2O)2}].37H2O (Na{SiW10Co2}2) and Na14[(A-alpha-SiW10O37)2{Ni4(OH)2(H2O)2}].77.5H2O (Na{SiW10Ni2}2), which were prepared by applying a new synthesis protocol and characterized thoroughly in the solid state by single-crystal and powder X-ray diffraction, IR spectroscopy, thermogravimetric analysis, and elemental analysis. Proteinase K was applied as a model protein and the polyoxotungstate (POT)-protein interactions of Na{SiW10Co2}2 and Na{SiW10Ni2}2 were studied side by side with the literature-known K5Na3[A-alpha-SiW9O34(OH)3{Co4(OAc)3}].28.5H2O ({SiW9Co4}) featuring the same number of transition metals. Testing the solution behavior of applied POTs under the crystallization conditions (sodium acetate buffer, pH 5.5) by time-dependent UV/vis spectroscopy and electrospray ionization mass spectrometry speciation studies revealed an initial dissociation of the sandwich POTs to the disubstituted Keggin anions HxNa5-x[SiW10Co2O38](3-) and HxNa5-x[SiW10Ni2O38](3-) ({SiW10M2}, M = Co(II) and Ni(II)) followed by partial rearrangement to the monosubstituted compounds (alpha-{SiW11Co} and alpha-{SiW11Ni}) after 1 week of aging. The protein crystal structure analysis revealed monosubstituted alpha-Keggin POTs in two conserved binding positions for all three investigated compounds, with one of these positions featuring a covalent attachment of the POT anion to an aspartate carboxylate. Despite the presence of both mono- and disubstituted anions in a crystallization mixture, proteinase K selectively binds to monosubstituted anions because of their preferred charge density for POT-protein interaction.

Speciation of Transition-Metal-Substituted Keggin-Type Silicotungstates Affected by the Co-crystallization Conditions with Proteinase K.,Breibeck J, Tanuhadi E, Gumerova NI, Giester G, Prado-Roller A, Rompel A Inorg Chem. 2021 Oct 18;60(20):15096-15100. doi: 10.1021/acs.inorgchem.1c02005., Epub 2021 Sep 16. PMID:34529407<ref>PMID:34529407</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 7a9k" style="background-color:#fffaf0;"></div>

==See Also==
*[[Proteinase 3D structures|Proteinase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Parengyodontium album]]
[[Category: Breibeck J]]
[[Category: Rompel A]]