View source for 1a2u


==STAPHYLOCOCCAL NUCLEASE, V23C VARIANT, COMPLEX WITH 1-N-BUTANE THIOL AND 3',5'-THYMIDINE DIPHOSPHATE==
<StructureSection load='1a2u' size='340' side='right'caption='[[1a2u]], [[Resolution|resolution]] 2.00&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1a2u]] 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=1A2U OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1A2U 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=BUC:S,S-BUTYLTHIOCYSTEINE'>BUC</scene>, <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=1a2u FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1a2u OCA], [https://pdbe.org/1a2u PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1a2u RCSB], [https://www.ebi.ac.uk/pdbsum/1a2u PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1a2u 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/a2/1a2u_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=1a2u ConSurf].
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== Publication Abstract from PubMed ==
The structures of several variants of staphylococcal nuclease with long flexible unnatural amino acid side chains in the hydrophobic core have been determined by X-ray crystallography. The unnatural amino acids are disulfide moieties between the lone cysteine residue in V23C nuclease and methane, ethane, 1-n-propane, 1-n-butane, 1-n-pentane, and 2-hydroxyethyl thiols. We have examined changes in the core packing of these mutants. Side chains as large as the 1-n-propyl cysteine disulfide can be incorporated without perturbation of the structure. This is due, in part, to cavities present in the wild-type protein. The longest side chains are not well defined, even though they remain buried within the protein interior. These results suggest that the enthalpy-entropy balance that governs the rigidity of protein interiors favors tight packing only weakly. Additionally, the tight packing observed normally in protein interiors may reflect, in part, the limited numbers of rotamers available to the natural amino acids.

Mobile unnatural amino acid side chains in the core of staphylococcal nuclease.,Wynn R, Harkins PC, Richards FM, Fox RO Protein Sci. 1996 Jun;5(6):1026-31. PMID:8762134<ref>PMID:8762134</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 1a2u" 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: Fox RO]]
[[Category: Harkins PC]]
[[Category: Richards FM]]
[[Category: Wynn R]]