3vm9: Difference between revisions
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[[ | ==Dimeric horse myoglobin== | ||
<StructureSection load='3vm9' size='340' side='right' caption='[[3vm9]], [[Resolution|resolution]] 1.05Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[3vm9]] is a 2 chain structure with sequence from [http://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 [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3VM9 FirstGlance]. <br> | |||
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><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'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3vm9 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3vm9 OCA], [http://www.rcsb.org/pdb/explore.do?structureId=3vm9 RCSB], [http://www.ebi.ac.uk/pdbsum/3vm9 PDBsum]</span></td></tr> | |||
</table> | |||
== Function == | |||
[[http://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®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
==See Also== | |||
*[[Myoglobin|Myoglobin]] | |||
== | == References == | ||
[[ | <references/> | ||
__TOC__ | |||
</StructureSection> | |||
[[Category: Equus caballus]] | [[Category: Equus caballus]] | ||
[[Category: Higuchi, Y | [[Category: Higuchi, Y]] | ||
[[Category: Hirota, S | [[Category: Hirota, S]] | ||
[[Category: Imai, K | [[Category: Imai, K]] | ||
[[Category: Nagao, S | [[Category: Nagao, S]] | ||
[[Category: Osuka, H | [[Category: Osuka, H]] | ||
[[Category: Shomura, Y | [[Category: Shomura, Y]] | ||
[[Category: Uni, T | [[Category: Uni, T]] | ||
[[Category: Yamada, T | [[Category: Yamada, T]] | ||
[[Category: Myoglobin]] | [[Category: Myoglobin]] | ||
[[Category: Oxygen binding]] | [[Category: Oxygen binding]] | ||
[[Category: Oxygen storage]] | [[Category: Oxygen storage]] | ||
[[Category: Oxygen transport]] | [[Category: Oxygen transport]] | ||
Revision as of 19:53, 24 December 2014
Dimeric horse myoglobinDimeric horse myoglobin
Structural highlights
Function[MYG_HORSE] Serves as a reserve supply of oxygen and facilitates the movement of oxygen within muscles. Publication Abstract from PubMedMyoglobin (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[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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