View source for 3bdc


==Crystal structure of Staphylococcal nuclease variant Delta+PHS at cryogenic temperature==
<StructureSection load='3bdc' size='340' side='right' caption='[[3bdc]], [[Resolution|resolution]] 1.80&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3bdc]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Staphylococcus_aureus Staphylococcus aureus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3BDC OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3BDC FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=THP:THYMIDINE-3,5-DIPHOSPHATE'>THP</scene></td></tr>
<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[2rbm|2rbm]], [[3c1e|3c1e]], [[3c1f|3c1f]], [[3d4d|3d4d]], [[3d6c|3d6c]], [[3dmu|3dmu]], [[3e5s|3e5s]], [[3eji|3eji]], [[3ero|3ero]], [[3erq|3erq]], [[3evq|3evq]]</td></tr>
<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Micrococcal_nuclease Micrococcal nuclease], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.31.1 3.1.31.1] </span></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3bdc FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3bdc OCA], [http://pdbe.org/3bdc PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=3bdc RCSB], [http://www.ebi.ac.uk/pdbsum/3bdc PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=3bdc ProSAT]</span></td></tr>
</table>
== Function ==
[[http://www.uniprot.org/uniprot/NUC_STAAW NUC_STAAW]] Enzyme that catalyzes the hydrolysis of both DNA and RNA at the 5' position of the phosphodiester bond (By similarity). 
== 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/bd/3bdc_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=3bdc ConSurf].
<div style="clear:both"></div>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Prior computational studies of the acid-unfolding behavior of staphylococcal nuclease (SNase) suggest that the pK(a) values of its carboxylic groups are difficult to reproduce with electrostatics calculations with continuum methods. To examine the molecular determinants of the pK(a) values of carboxylic groups in SNase, the pK(a) values of all 20 Asp and Glu residues were measured with multidimensional and multinuclear NMR spectroscopy in an acid insensitive variant of SNase. The crystal structure of the protein was obtained to describe the microenvironments of the carboxylic groups. Fourteen Asp and Glu residues titrate with relatively normal pK(a) values that are depressed by less than 1.1 units relative to the normal pK(a) of Asp and Glu in water. Only six residues have pK(a) values shifted by more than 1.5 units. Asp-21 has an unusually high pK(a) of 6.5, which is probably the result of interactions with other carboxylic groups at the active site. The most perturbed pK(a) values appear to be governed by hydrogen bonding and not by Coulomb interactions. The pK(a) values calculated with standard continuum electrostatics methods applied to static structures are more depressed than the measured values because Coulomb effects are exaggerated in the calculations. The problems persist even when the protein is treated with the dielectric constant of water. This can be interpreted to imply that structural relaxation is an important determinant of the pK(a) values; however, no major pH-sensitive conformational reorganization of the backbone was detected using NMR spectroscopy. Proteins 2009. (c) 2009 Wiley-Liss, Inc.

Molecular determinants of the pK(a) values of Asp and Glu residues in staphylococcal nuclease.,Castaneda CA, Fitch CA, Majumdar A, Khangulov V, Schlessman JL, Garcia-Moreno BE Proteins. 2009 May 4;77(3):570-588. PMID:19533744<ref>PMID:19533744</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 3bdc" style="background-color:#fffaf0;"></div>

==See Also==
*[[Staphylococcal nuclease|Staphylococcal nuclease]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Micrococcal nuclease]]
[[Category: Staphylococcus aureus]]
[[Category: Garcia-Moreno, B E]]
[[Category: Khangulov, V]]
[[Category: Schlessman, J L]]
[[Category: Hydrolase]]
[[Category: Hyperstable variant]]
[[Category: Pdtp]]
[[Category: Staphylococcal nuclease]]