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[[Image:1mgn.gif|left|200px]]<br /><applet load="1mgn" size="350" color="white" frame="true" align="right" spinBox="true"
caption="1mgn, resolution 1.9&Aring;" />
'''HIS64(E7)-> TYR APOMYOGLOBIN AS A REAGENT FOR MEASURING RATES OF HEMIN DISSOCIATION'''<br />


==Overview==
==HIS64(E7)-> TYR APOMYOGLOBIN AS A REAGENT FOR MEASURING RATES OF HEMIN DISSOCIATION==
To develop an assay for hemin dissociation, His64(E7) was replaced by Tyr in sperm whale myoglobin producing a holoprotein with a distinct green color due to an intense absorption band at 600 nm. Val68(E11) was replaced by Phe in the same protein to increase its stability. When excess Tyr64-Val68 apoglobin is mixed with either metmyoglobin or methemoglobin, the solution turns from brown to green, and the absorbance changes can be used to measure complete time courses for hemin dissociation from either holoprotein. This assay has been used to measure rates of hemin dissociation from native metmyoglobin, four myoglobin mutants (Ala64(E7), Ala68(E11), Phe68(E11), and Glu45(CD3)), native methemoglobin, valence hybrid hemoglobins, and two mutant hemoglobins ((alpha(Gly-E7)beta(native))2, and (alpha(native)beta(Gly-E7))2). Two kinetic phases were observed for hemin dissociation from native human hemoglobin at pH 7.0 and 37 degrees C. Valence and mutant hybrid hemoglobins were used to assign the faster phase (k = 7.8 +/- 2.0 h-1) to hemin dissociation from ferric beta subunits and the slower (k = 0.6 +/- 0.15 h-1) to dissociation from alpha subunits. The corresponding rate for wild-type metmyoglobin is 0.007 +/- 0.004 h-1.
<StructureSection load='1mgn' size='340' side='right'caption='[[1mgn]], [[Resolution|resolution]] 1.90&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1mgn]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Physeter_catodon Physeter catodon]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1MGN OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1MGN 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]] 1.9&#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=SO4:SULFATE+ION'>SO4</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=1mgn FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1mgn OCA], [https://pdbe.org/1mgn PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1mgn RCSB], [https://www.ebi.ac.uk/pdbsum/1mgn PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1mgn ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/MYG_PHYMC MYG_PHYMC] Serves as a reserve supply of oxygen and facilitates the movement of oxygen within muscles.
== 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/mg/1mgn_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=1mgn ConSurf].
<div style="clear:both"></div>


==About this Structure==
==See Also==
1MGN is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Physeter_catodon Physeter catodon] with <scene name='pdbligand=SO4:'>SO4</scene> and <scene name='pdbligand=HEM:'>HEM</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1MGN OCA].
*[[Myoglobin 3D structures|Myoglobin 3D structures]]
 
__TOC__
==Reference==
</StructureSection>
His64(E7)--&gt;Tyr apomyoglobin as a reagent for measuring rates of hemin dissociation., Hargrove MS, Singleton EW, Quillin ML, Ortiz LA, Phillips GN Jr, Olson JS, Mathews AJ, J Biol Chem. 1994 Feb 11;269(6):4207-14. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=8307983 8307983]
[[Category: Large Structures]]
[[Category: Physeter catodon]]
[[Category: Physeter catodon]]
[[Category: Single protein]]
[[Category: Hargrove MS]]
[[Category: Hargrove, M S.]]
[[Category: Phillips Jr GN]]
[[Category: Jr., G N.Phillips.]]
[[Category: Quillin ML]]
[[Category: Quillin, M L.]]
[[Category: HEM]]
[[Category: SO4]]
[[Category: oxygen transport]]
 
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