View source for 1cpe


==A CATION BINDING MOTIF STABILIZES THE COMPOUND I RADICAL OF CYTOCHROME C PEROXIDASE==
<StructureSection load='1cpe' size='340' side='right'caption='[[1cpe]], [[Resolution|resolution]] 2.20&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1cpe]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Saccharomyces_cerevisiae Saccharomyces cerevisiae]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1CPE OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1CPE 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]] 2.2&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=HEM:PROTOPORPHYRIN+IX+CONTAINING+FE'>HEM</scene>, <scene name='pdbligand=K:POTASSIUM+ION'>K</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=1cpe FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1cpe OCA], [https://pdbe.org/1cpe PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1cpe RCSB], [https://www.ebi.ac.uk/pdbsum/1cpe PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1cpe ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/CCPR_YEAST CCPR_YEAST] Destroys radicals which are normally produced within the cells and which are toxic to biological systems.
== 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/cp/1cpe_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=1cpe ConSurf].
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== Publication Abstract from PubMed ==
Cytochrome c peroxidase reacts with peroxide to form compound I, which contains an oxyferryl heme and an indolyl radical at Trp-191. The indolyl free radical has a half-life of several hours at room temperature, and this remarkable stability is essential for the catalytic function of cytochrome c peroxidase. To probe the protein environment that stabilizes the compound I radical, we used site-directed mutagenesis to replace Trp-191 with Gly or Gln. Crystal structures of these mutants revealed a monovalent cation binding site in the cavity formerly occupied by the side chain of Trp-191. Comparison of this site with those found in other known cation binding enzymes shows that the Trp-191 side chain resides in a consensus K+ binding site. Electrostatic potential calculations indicate that the cation binding site is created by partial negative charges at the backbone carbonyl oxygen atoms of residues 175 and 177, the carboxyl end of a long alpha-helix (residues 165-175), the heme propionates, and the carboxylate side chain of Asp-235. These features create a negative potential that envelops the side chain of Trp-191; the calculated free energy change for cation binding in this site is -27 kcal/mol (1 cal = 4.184J). This is more than sufficient to account for the stability of the Trp-191 radical, which our estimates suggest is stabilized by 7.8 kcal/mol relative to a Trp radical in solution.

A cation binding motif stabilizes the compound I radical of cytochrome c peroxidase.,Miller MA, Han GW, Kraut J Proc Natl Acad Sci U S A. 1994 Nov 8;91(23):11118-22. PMID:7972020<ref>PMID:7972020</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 1cpe" style="background-color:#fffaf0;"></div>

==See Also==
*[[Cytochrome c peroxidase 3D structures|Cytochrome c peroxidase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Saccharomyces cerevisiae]]
[[Category: Han GW]]
[[Category: Kraut J]]
[[Category: Miller MA]]