View source for 3nhh


==Crystal structure of Staphylococcal nuclease variant V23E-L36K at cryogenic temperature==
<StructureSection load='3nhh' size='340' side='right'caption='[[3nhh]], [[Resolution|resolution]] 2.00&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3nhh]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Staphylococcus_aureus Staphylococcus aureus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3NHH OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3NHH 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&#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=THP:THYMIDINE-3,5-DIPHOSPHATE'>THP</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=3nhh FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3nhh OCA], [https://pdbe.org/3nhh PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3nhh RCSB], [https://www.ebi.ac.uk/pdbsum/3nhh PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3nhh ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/NUC_STAAU NUC_STAAU] Enzyme that catalyzes the hydrolysis of both DNA and RNA at the 5' position of the phosphodiester bond.
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/nh/3nhh_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=3nhh ConSurf].
<div style="clear:both"></div>
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== Publication Abstract from PubMed ==
An artificial charge pair buried in the hydrophobic core of staphylococcal nuclease was engineered by making the V23E and L36K substitutions. Buried individually, Glu-23 and Lys-36 both titrate with pKa values near 7. When buried together their pKa values appear to be normal. The ionizable moieties of the buried Glu-Lys pair are 2.6 A apart. The interaction between them at pH 7 is worth 5 kcal/mol. Despite this strong interaction, the buried Glu-Lys pair destabilizes the protein significantly because the apparent Coulomb interaction is sufficient to offset the dehydration of only one of the two buried charges. Save for minor reorganization of dipoles and water penetration consistent with the relatively high dielectric constant reported by the buried ion pair, there is no evidence that the presence of two charges in the hydrophobic interior of the protein induces any significant structural reorganization. The successful engineering of an artificial ion pair in a highly hydrophobic environment suggests that buried Glu-Lys pairs in dehydrated environments can be charged and that it is possible to engineer charge clusters that loosely resemble catalytic sites in a scaffold protein with high thermodynamic stability, without the need for specialized structural adaptations.

Structural and thermodynamic consequences of burial of an artificial ion pair in the hydrophobic interior of a protein.,Robinson AC, Castaneda CA, Schlessman JL, Garcia-Moreno E B Proc Natl Acad Sci U S A. 2014 Aug 12;111(32):11685-90. doi:, 10.1073/pnas.1402900111. Epub 2014 Jul 29. PMID:25074910<ref>PMID:25074910</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 3nhh" style="background-color:#fffaf0;"></div>

==See Also==
*[[Staphylococcal nuclease 3D structures|Staphylococcal nuclease 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Staphylococcus aureus]]
[[Category: Garcia-Moreno EB]]
[[Category: Robinson AC]]
[[Category: Schlessman JL]]