1js8
From Proteopedia
(New page: 200px<br /><applet load="1js8" size="450" color="white" frame="true" align="right" spinBox="true" caption="1js8, resolution 2.3Å" /> '''Structure of a Functi...) |
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| - | [[Image:1js8.gif|left|200px]]<br /><applet load="1js8" size=" | + | [[Image:1js8.gif|left|200px]]<br /><applet load="1js8" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1js8, resolution 2.3Å" /> | caption="1js8, resolution 2.3Å" /> | ||
'''Structure of a Functional Unit from Octopus Hemocyanin'''<br /> | '''Structure of a Functional Unit from Octopus Hemocyanin'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Hemocyanins are giant oxygen transport proteins found in many arthropods | + | Hemocyanins are giant oxygen transport proteins found in many arthropods and molluscs. Freely dissolved in the hemolymph, they are multisubunit proteins that contain many copies of the active site, a copper atom pair that reversibly binds oxygen. Octopus hemocyanin is composed of ten subunits, each of which contain seven oxygen-binding "functional units". The carboxyl-terminal 47 kDa functional unit, Odg, is a proteolytic isolate that binds oxygen reversibly while exhibiting slight Bohr and magnesium ion effects. In this work we present the X-ray structure determination and analysis of Odg at 2.3 A resolution. Odg has two structural domains: a largely alpha-helical copper binding domain, and a five-stranded anti-parallel beta-sandwich with the jelly roll topology found in many viruses. Six histidine residues ligate the copper atoms, one of which is involved in a thioether bridge. The results show that the hemocyanin from the mollusc and that from the arthropod have distinct tertiary folds in addition to the long recognized differences in their quaternary structures. Nonetheless, a comparison of Octopus and horseshoe crab hemocyanin reveals a similar active site, in a striking example of perhaps both convergent and divergent evolution. |
==About this Structure== | ==About this Structure== | ||
| - | 1JS8 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Octopus_dofleini Octopus dofleini] with MAN and CUO as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | + | 1JS8 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Octopus_dofleini Octopus dofleini] with <scene name='pdbligand=MAN:'>MAN</scene> and <scene name='pdbligand=CUO:'>CUO</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1JS8 OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Octopus dofleini]] | [[Category: Octopus dofleini]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Cuff, M | + | [[Category: Cuff, M E.]] |
| - | [[Category: Hendrickson, W | + | [[Category: Hendrickson, W A.]] |
| - | [[Category: Holde, K | + | [[Category: Holde, K E.van.]] |
| - | [[Category: Miller, K | + | [[Category: Miller, K I.]] |
[[Category: CUO]] | [[Category: CUO]] | ||
[[Category: MAN]] | [[Category: MAN]] | ||
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[[Category: thioether bond]] | [[Category: thioether bond]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:26:10 2008'' |
Revision as of 11:26, 21 February 2008
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Structure of a Functional Unit from Octopus Hemocyanin
Overview
Hemocyanins are giant oxygen transport proteins found in many arthropods and molluscs. Freely dissolved in the hemolymph, they are multisubunit proteins that contain many copies of the active site, a copper atom pair that reversibly binds oxygen. Octopus hemocyanin is composed of ten subunits, each of which contain seven oxygen-binding "functional units". The carboxyl-terminal 47 kDa functional unit, Odg, is a proteolytic isolate that binds oxygen reversibly while exhibiting slight Bohr and magnesium ion effects. In this work we present the X-ray structure determination and analysis of Odg at 2.3 A resolution. Odg has two structural domains: a largely alpha-helical copper binding domain, and a five-stranded anti-parallel beta-sandwich with the jelly roll topology found in many viruses. Six histidine residues ligate the copper atoms, one of which is involved in a thioether bridge. The results show that the hemocyanin from the mollusc and that from the arthropod have distinct tertiary folds in addition to the long recognized differences in their quaternary structures. Nonetheless, a comparison of Octopus and horseshoe crab hemocyanin reveals a similar active site, in a striking example of perhaps both convergent and divergent evolution.
About this Structure
1JS8 is a Single protein structure of sequence from Octopus dofleini with and as ligands. Full crystallographic information is available from OCA.
Reference
Crystal structure of a functional unit from Octopus hemocyanin., Cuff ME, Miller KI, van Holde KE, Hendrickson WA, J Mol Biol. 1998 May 15;278(4):855-70. PMID:9614947
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