2rks: Difference between revisions

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-{{STRUCTURE_2rks|  PDB=2rks  |  SCENE=  }}
+==Crystal structure of Staphylococcal nuclease variant PHS L38K at cryogenic temperature==
-===Crystal structure of Staphylococcal nuclease variant PHS L38K at cryogenic temperature===
+<StructureSection load='2rks' size='340' side='right' caption='[[2rks]], [[Resolution|resolution]] 2.01&Aring;' scene=''>
-{{ABSTRACT_PUBMED_18369193}}
+== Structural highlights ==
+<table><tr><td colspan='2'>[[2rks]] 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=2RKS OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2RKS FirstGlance]. <br>
+</td></tr><tr><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=PO4:PHOSPHATE+ION'>PO4</scene><br>
+<tr><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[2rbm|2rbm]]</td></tr>
+<tr><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">nuc ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=1280 Staphylococcus aureus])</td></tr>
+<tr><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><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2rks FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2rks OCA], [http://www.rcsb.org/pdb/explore.do?structureId=2rks RCSB], [http://www.ebi.ac.uk/pdbsum/2rks PDBsum]</span></td></tr>
+<table>
+== 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/rk/2rks_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/chain_selection.php?pdb_ID=2ata ConSurf].
+<div style="clear:both"></div>
+<div style="background-color:#fffaf0;">
+== Publication Abstract from PubMed ==
+Previously we reported that Lys, Asp, and Glu residues at positions 66 and 92 in staphylococcal nuclease (SNase) titrate with pK(a) values shifted by up to 5 pK(a) units in the direction that promotes the neutral state. In contrast, the internal Lys-38 in SNase titrates with a normal pK(a). The crystal structure of the L38K variant shows that the side chain of Lys-38 is buried. The ionizable moiety is approximately 7 A from solvent and ion paired with Glu-122. This suggests that the pK(a) value of Lys-38 is normal because the energetic penalty for dehydration is offset by a favorable Coulomb interaction. However, the pK(a) of Lys-38 was also normal when Glu-122 was replaced with Gln or with Ala. Continuum electrostatics calculations were unable to reproduce the pK(a) of Lys-38 unless the protein was treated with an artificially high dielectric constant, consistent with structural reorganization being responsible for the normal pK(a) value of Lys-38. This reorganization must be local because circular dichroism and NMR spectroscopy indicate that the L38K protein is native-like under all conditions studied. In molecular dynamics simulations, the ion pair between Lys-38 and Glu-122 is unstable. The simulations show that a minor rearrangement of a loop is sufficient to allow penetration of water to the amino moiety of Lys-38. This illustrates both the important roles of local flexibility and water penetration as determinants of pK(a) values of ionizable groups buried near the protein-water interface, and the challenges faced by structure-based pK(a) calculations in reproducing these effects.
-==Function==
+A buried lysine that titrates with a normal pKa: role of conformational flexibility at the protein-water interface as a determinant of pKa values.,Harms MJ, Schlessman JL, Chimenti MS, Sue GR, Damjanovic A, Garcia-Moreno B Protein Sci. 2008 May;17(5):833-45. Epub 2008 Mar 27. PMID:18369193<ref>PMID:18369193</ref>
-[[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).
-==About this Structure==
+From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
-[[2rks]] 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=2RKS OCA].
+</div>
-==Reference==
+==See Also==
-<ref group="xtra">PMID:018369193</ref><references group="xtra"/><references/>
+*[[Staphylococcal nuclease|Staphylococcal nuclease]]
+== References ==
+<references/>
+__TOC__
+</StructureSection>
 [[Category: Micrococcal nuclease]]
 [[Category: Staphylococcus aureus]]