View source for 1raq


==THE STRUCTURE AND FUNCTION OF OMEGA LOOP A REPLACEMENTS IN CYTOCHROME C==
<StructureSection load='1raq' size='340' side='right'caption='[[1raq]], [[Resolution|resolution]] 1.90&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1raq]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Atcc_18824 Atcc 18824]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1RAQ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1RAQ FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=HEC:HEME+C'>HEC</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene></td></tr>
<tr id='NonStdRes'><td class="sblockLbl"><b>[[Non-Standard_Residue|NonStd Res:]]</b></td><td class="sblockDat"><scene name='pdbligand=M3L:N-TRIMETHYLLYSINE'>M3L</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=1raq FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1raq OCA], [https://pdbe.org/1raq PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1raq RCSB], [https://www.ebi.ac.uk/pdbsum/1raq PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1raq ProSAT]</span></td></tr>
</table>
== Function ==
[[https://www.uniprot.org/uniprot/CYC1_YEAST CYC1_YEAST]] Electron carrier protein. The oxidized form of the cytochrome c heme group can accept an electron from the heme group of the cytochrome c1 subunit of cytochrome reductase. Cytochrome c then transfers this electron to the cytochrome oxidase complex, the final protein carrier in the mitochondrial electron-transport chain. 
== 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/ra/1raq_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=1raq ConSurf].
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== Publication Abstract from PubMed ==
The structural and functional consequences of replacing omega-loop A (residues 18-32) in yeast iso-1-cytochrome c with the corresponding loop of Rhodospirillum rubrum cytochrome c2 have been examined. The three-dimensional structure of this loop replacement mutant RepA2 cytochrome c, and a second mutant RepA2(Val 20) cytochrome c in which residue 20 was back substituted to valine, were determined using X-ray diffraction techniques. A change in the molecular packing is evident in the RepA2 mutant protein, which has a phenylalanine at position 20, a residue considerably larger than the valine found in wild-type yeast iso-1-cytochrome c. The side chain of Phe 20 is redirected toward the molecular surface, altering the packing of this region of omega-loop A with the hydrophobic core of the protein. In the RepA2(Val 20) structure, omega-loop A contains a valine at position 20, which restores the original wild-type packing arrangement of the hydrophobic core. Also, as a result of omega-loop A replacement, residue 26 is changed from a histidine to asparagine, which results in displacements of the main-chain atoms near residue 44 to which residue 26 is hydrogen bonded. In vivo studies of the growth rate of the mutant strains on nonfermentable media indicate that the RepA2(Val 20) cytochrome c behaves much like the wild-type yeast iso-1 protein, whereas the stability and function of the RepA2 cytochrome c showed a temperature dependence. The midpoint reduction potential measured by cyclic voltammetry of the RepA2 mutant is 271 mV at 25 degrees C. This is 19 mV less than the wild-type and RepA2(Val 20) proteins (290 mV) and may result from disruption of the hydrophobic packing in the heme pocket and increased mobility of omega-loop A in RepA2 cytochrome c. The temperature dependence of the reduction potential is also greatly enhanced in the RepA2 protein.

The structure and function of omega loop A replacements in cytochrome c.,Murphy ME, Fetrow JS, Burton RE, Brayer GD Protein Sci. 1993 Sep;2(9):1429-40. PMID:8401228<ref>PMID:8401228</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 1raq" style="background-color:#fffaf0;"></div>

==See Also==
*[[Cytochrome C 3D structures|Cytochrome C 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Atcc 18824]]
[[Category: Large Structures]]
[[Category: Brayer, G D]]
[[Category: Murphy, M E.P]]
[[Category: Electron transport]]