View source for 3vm9


==Dimeric horse myoglobin==
<StructureSection load='3vm9' size='340' side='right'caption='[[3vm9]], [[Resolution|resolution]] 1.05&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3vm9]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Equus_caballus Equus caballus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3VM9 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3VM9 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]] 1.05&#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=O:OXYGEN+ATOM'>O</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=3vm9 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3vm9 OCA], [https://pdbe.org/3vm9 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3vm9 RCSB], [https://www.ebi.ac.uk/pdbsum/3vm9 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3vm9 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/MYG_HORSE MYG_HORSE] Serves as a reserve supply of oxygen and facilitates the movement of oxygen within muscles.
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Myoglobin (Mb) stores dioxygen in muscles, and is a fundamental model protein widely used in molecular design. The presence of dimeric Mb has been known for more than forty years, but its structural and oxygen binding properties remain unknown. From an X-ray crystallographic analysis at 1.05 A resolution, we found that dimeric metMb exhibits a domain-swapped structure with two extended alpha-helices. Each new long alpha-helix is formed by the E and F helices and the EF-loop of the original monomer, and as a result the proximal and distal histidines of the heme originate from different protomers. The heme orientation in the dimer was in the normal mode as in the monomer, but regulated faster from the reverse to normal orientation. The dimer possessed the oxygen binding property, although it exhibited a slightly higher oxygen binding affinity ( approximately 1.4 fold) compared to the monomer and showed no cooperativity for oxygen binding. The oxygen binding rate constant (k(on)) of the dimer ((14.0 +/- 0.7) x 10(6) M(-1) s(-1)) was similar to that of the monomer, whereas the oxygen dissociation rate constant (k(off)) of the dimer (8 +/- 1 s(-1)) was smaller than that of the monomer (12 +/- 1 s(-1)). We attribute the similar k(on) values to their active site structures being similar, whereas the faster regulation of the heme orientation and the smaller k(off) in the dimer are presumably due to the slight change in the active site structure and/or more rigid structure compared to the monomer. These results show that domain swapping may be a new tool for protein engineering.

Structural and oxygen binding properties of dimeric horse myoglobin.,Nagao S, Osuka H, Yamada T, Uni T, Shomura Y, Imai K, Higuchi Y, Hirota S Dalton Trans. 2012 Oct 7;41(37):11378-85. Epub 2012 Aug 13. PMID:22885714<ref>PMID:22885714</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 3vm9" style="background-color:#fffaf0;"></div>

==See Also==
*[[Myoglobin 3D structures|Myoglobin 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Equus caballus]]
[[Category: Large Structures]]
[[Category: Higuchi Y]]
[[Category: Hirota S]]
[[Category: Imai K]]
[[Category: Nagao S]]
[[Category: Osuka H]]
[[Category: Shomura Y]]
[[Category: Uni T]]
[[Category: Yamada T]]