View source for 3fd7


==Crystal structure of Onconase C87A/C104A-ONC==
<StructureSection load='3fd7' size='340' side='right'caption='[[3fd7]], [[Resolution|resolution]] 1.53&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3fd7]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Lithobates_pipiens Lithobates pipiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3FD7 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3FD7 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]] 1.531&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=EDO:1,2-ETHANEDIOL'>EDO</scene>, <scene name='pdbligand=GOL:GLYCEROL'>GOL</scene>, <scene name='pdbligand=PCA:PYROGLUTAMIC+ACID'>PCA</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=3fd7 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3fd7 OCA], [https://pdbe.org/3fd7 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3fd7 RCSB], [https://www.ebi.ac.uk/pdbsum/3fd7 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3fd7 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/RNP30_LITPI RNP30_LITPI] Basic protein with antiproliferative/cytotoxic activity against several tumor cell lines in vitro, as well as antitumor in vivo. It exhibits a ribonuclease-like activity against high molecular weight ribosomal RNA.
== 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/fd/3fd7_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.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=3fd7 ConSurf].
<div style="clear:both"></div>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
The two homologous proteins ribonuclease A and onconase fold through conserved initial contacts but differ significantly in their thermodynamic stability. A disulfide bond is located in the folding initiation site of onconase (the C-terminal part of the protein molecule) that is missing in ribonuclease A, whereas the other three disulfide bonds of onconase are conserved in ribonuclease A. Consequently, the deletion of this C-terminal disulfide bond (C87-C104) allows the impact of the contacts in this region on the folding of onconase to be studied. We found the C87A/C104A-onconase variant to be less active and less stable than the wild-type protein, whereas the tertiary structure, which was determined by both X-ray crystallography and NMR spectroscopy, was only marginally affected. The folding kinetics of the variant, however, were found to be changed considerably in comparison to wild-type onconase. Proton exchange experiments in combination with two-dimensional NMR spectroscopy revealed differences in the native-state dynamics of the two proteins in the folding initiation site, which are held responsible for the changed folding mechanism. Likewise, the molecular dynamics simulation of the unfolding reaction indicated disparities for both proteins. Our results show that the high stability of onconase is based on the efficient stabilization of the folding initiation site by the C-terminal disulfide bond. The formation of the on-pathway intermediate, which is detectable during the folding of the wild-type protein and promotes the fast and efficient refolding reaction, requires the presence of this covalent bond.

Impact of the C-terminal disulfide bond on the folding and stability of onconase.,Schulenburg C, Weininger U, Neumann P, Meiselbach H, Stubbs MT, Sticht H, Balbach J, Ulbrich-Hofmann R, Arnold U Chembiochem. 2010 May 3;11(7):978-86. PMID:20349493<ref>PMID:20349493</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 3fd7" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Lithobates pipiens]]
[[Category: Arnold U]]
[[Category: Neumann P]]
[[Category: Schulenburg C]]
[[Category: Stubbs MT]]
[[Category: Ulbrich-Hofmann R]]