View source for 1awp


==RAT OUTER MITOCHONDRIAL MEMBRANE CYTOCHROME B5==
<StructureSection load='1awp' size='340' side='right'caption='[[1awp]], [[Resolution|resolution]] 2.00&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1awp]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Rattus_norvegicus Rattus norvegicus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1AWP OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1AWP 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&#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=1awp FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1awp OCA], [https://pdbe.org/1awp PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1awp RCSB], [https://www.ebi.ac.uk/pdbsum/1awp PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1awp ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/CYB5B_RAT CYB5B_RAT] Cytochrome b5 is a membrane bound hemoprotein which function as an electron carrier for several membrane bound oxygenases.
== 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/aw/1awp_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=1awp ConSurf].
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== Publication Abstract from PubMed ==
When the reduction potential of cytochrome b5 is measured with the aid of several different surface-modified electrodes that function on the basis of electrostatic interactions with the protein, the resultant values have been consistently more positive (40-100 mV) than the reduction potentials measured with potentiometric methods. In this paper, we report that the heme edge containing the exposed heme propionate, a heme methyl, and a heme vinyl, and which constitutes part of the surface of cytochrome b5, modulates its reduction potential. The positive shifts observed in the voltammetric measurements appear to originate from the formation of a complex between cytochrome b5 and the modified electrode surface which (a) neutralizes the charge on the heme propionate located on the exposed heme edge and (b) lowers the dielectric of the exposed heme microenvironment by excluding water from the complex interface, factors which result in the destabilization of the positive charge on the ferric heme with respect to the neutral ferrous heme. The observed positive shift, which is induced by complexation at the electrode surface, may indicate that similar shifts in the reduction potential of cytochrome b5 occur when it forms a complex with physiological partners, prior to electron transfer. The effect of the value of the dielectric constant on the reduction potential of cytochrome b5 was corroborated by preparing the V45L/V61L double mutant whose reduction potential was measured to be 50 mV more negative than the value measured for the wild type protein. The negative shift in the reduction potential of the mutant protein was explained by the increased accessibility of water to the heme binding site, as observed in its X-ray crystal structure.

The reduction potential of cytochrome b5 is modulated by its exposed heme edge.,Rivera M, Seetharaman R, Girdhar D, Wirtz M, Zhang X, Wang X, White S Biochemistry. 1998 Feb 10;37(6):1485-94. PMID:9484218<ref>PMID:9484218</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 1awp" style="background-color:#fffaf0;"></div>

==See Also==
*[[Cytochrome b5 3D structures|Cytochrome b5 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Rattus norvegicus]]
[[Category: Wang X]]
[[Category: Zhang X]]