View source for 1z5f


==Solution Structure of the Cytotoxic RC-RNase 3 with a Pyroglutamate Residue at the N-terminus==
<StructureSection load='1z5f' size='340' side='right'caption='[[1z5f]]' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1z5f]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Lithobates_catesbeianus Lithobates catesbeianus]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1Z5F OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1Z5F FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Solution NMR, 20 models</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=PCA:PYROGLUTAMIC+ACID'>PCA</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=1z5f FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1z5f OCA], [https://pdbe.org/1z5f PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1z5f RCSB], [https://www.ebi.ac.uk/pdbsum/1z5f PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1z5f ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/Q9DFY7_AQUCT Q9DFY7_AQUCT] 
== 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/z5/1z5f_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=1z5f ConSurf].
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== Publication Abstract from PubMed ==
Many proteins and bioactive peptides contain an N-terminal pyroglutamate residue (Pyr1). This residue reduces the susceptibility of the protein to aminopeptidases and often has important functional roles. The antitumor ribonuclease RC-RNase 3 (RNase 3) from oocytes of Rana catesbeiana (bullfrog) is one such protein. We have produced recombinant RNase 3 containing the N-terminal Pyr1 (pRNase 3) and found it to be indistinguishable from the native RNase 3 by mass spectrometry and a variety of other biochemical and immunological criteria. We demonstrated by NMR analysis that the Pyr1 of pRNase 3 forms hydrogen bonds with Lys9 and Ile96 and stabilizes the N-terminal alpha-helix in a rigid conformation. In contrast, the N-terminal alpha-helix becomes flexible and the pKa values of the catalytic residues His10 and His97 altered when Pyr1 formation is blocked by an extra methionine at the N terminus in the recombinant mqRNase 3. Thus, our results provide a mechanistic explanation on the essential role of Pyr1 in maintaining the structural integrity, especially at the N-terminal alpha-helix, and in providing the proper environment for the ionization of His10 and His97 residues for catalysis and cytotoxicity against HeLa cells.

Roles of N-terminal pyroglutamate in maintaining structural integrity and pKa values of catalytic histidine residues in bullfrog ribonuclease 3.,Lou YC, Huang YC, Pan YR, Chen C, Liao YD J Mol Biol. 2006 Jan 20;355(3):409-21. Epub 2005 Nov 10. PMID:16309702<ref>PMID:16309702</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 1z5f" style="background-color:#fffaf0;"></div>

==See Also==
*[[Ribonuclease 3D structures|Ribonuclease 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Lithobates catesbeianus]]
[[Category: Chen C]]
[[Category: Huang YC]]
[[Category: Liao YD]]
[[Category: Lou YC]]
[[Category: Pan YR]]