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[[Image:1cmt.gif|left|200px]]<br /><applet load="1cmt" size="350" color="white" frame="true" align="right" spinBox="true"
caption="1cmt, resolution 2.1&Aring;" />
'''THE ROLE OF ASPARTATE-235 IN THE BINDING OF CATIONS TO AN ARTIFICIAL CAVITY AT THE RADICAL SITE OF CYTOCHROME C PEROXIDASE'''<br />


==Overview==
==THE ROLE OF ASPARTATE-235 IN THE BINDING OF CATIONS TO AN ARTIFICIAL CAVITY AT THE RADICAL SITE OF CYTOCHROME C PEROXIDASE==
The activated state of cytochrome c peroxidase, compound ES, contains a cation radical on the Trp-191 side chain. We recently reported that replacing this tryptophan with glycine creates a buried cavity at the active site that contains ordered solvent and that will specifically bind substituted imidazoles in their protonated cationic forms (Fitzgerald MM, Churchill MJ, McRee DE, Goodin DB, 1994, Biochemistry 33:3807-3818). Proposals that a nearby carboxylate, Asp-235, and competing monovalent cations should modulate the affinity of the W191G cavity for ligand binding are addressed in this study. Competitive binding titrations of the imidazolium ion to W191G as a function of [K+] show that potassium competes weakly with the binding of imidazoles. The dissociation constant observed for potassium binding (18 mM) is more than 3,000-fold higher than that for 1,2-dimethylimidazole (5.5 microM) in the absence of competing cations. Significantly, the W191G-D235N double mutant shows no evidence for binding imidazoles in their cationic or neutral forms, even though the structure of the cavity remains largely unperturbed by replacement of the carboxylate. Refined crystallographic B-values of solvent positions indicate that the weakly bound potassium in W191G is significantly depopulated in the double mutant. These results demonstrate that the buried negative charge of Asp-235 is an essential feature of the cation binding determinant and indicate that this carboxylate plays a critical role in stabilizing the formation of the Trp-191 radical cation.
<StructureSection load='1cmt' size='340' side='right'caption='[[1cmt]], [[Resolution|resolution]] 2.10&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1cmt]] 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=1CMT OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1CMT 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]] 2.1&#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></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=1cmt FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1cmt OCA], [https://pdbe.org/1cmt PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1cmt RCSB], [https://www.ebi.ac.uk/pdbsum/1cmt PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1cmt 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/cm/1cmt_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=1cmt ConSurf].
<div style="clear:both"></div>


==About this Structure==
==See Also==
1CMT is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Saccharomyces_cerevisiae Saccharomyces cerevisiae] with <scene name='pdbligand=HEM:'>HEM</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Cytochrome-c_peroxidase Cytochrome-c peroxidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.11.1.5 1.11.1.5] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1CMT OCA].
*[[Cytochrome c peroxidase 3D structures|Cytochrome c peroxidase 3D structures]]
 
__TOC__
==Reference==
</StructureSection>
The role of aspartate-235 in the binding of cations to an artificial cavity at the radical site of cytochrome c peroxidase., Fitzgerald MM, Trester ML, Jensen GM, McRee DE, Goodin DB, Protein Sci. 1995 Sep;4(9):1844-50. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=8528082 8528082]
[[Category: Large Structures]]
[[Category: Cytochrome-c peroxidase]]
[[Category: Saccharomyces cerevisiae]]
[[Category: Saccharomyces cerevisiae]]
[[Category: Single protein]]
[[Category: Fitzgerald MM]]
[[Category: Fitzgerald, M M.]]
[[Category: Goodin DB]]
[[Category: Goodin, D B.]]
[[Category: Jensen GM]]
[[Category: Jensen, G M.]]
[[Category: Mcree DE]]
[[Category: Mcree, D E.]]
[[Category: Trester ML]]
[[Category: Trester, M L.]]
[[Category: HEM]]
[[Category: oxidoreductase (h2o2(a))]]
 
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:07:39 2008''

Latest revision as of 09:43, 7 February 2024

THE ROLE OF ASPARTATE-235 IN THE BINDING OF CATIONS TO AN ARTIFICIAL CAVITY AT THE RADICAL SITE OF CYTOCHROME C PEROXIDASETHE ROLE OF ASPARTATE-235 IN THE BINDING OF CATIONS TO AN ARTIFICIAL CAVITY AT THE RADICAL SITE OF CYTOCHROME C PEROXIDASE

Structural highlights

1cmt is a 1 chain structure with sequence from Saccharomyces cerevisiae. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 2.1Å
Ligands:
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

CCPR_YEAST Destroys radicals which are normally produced within the cells and which are toxic to biological systems.

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

See Also

1cmt, resolution 2.10Å

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