1ash
From Proteopedia
(New page: 200px<br /> <applet load="1ash" size="450" color="white" frame="true" align="right" spinBox="true" caption="1ash, resolution 2.15Å" /> '''THE STRUCTURE OF AS...) |
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| - | [[Image:1ash.gif|left|200px]]<br /> | + | [[Image:1ash.gif|left|200px]]<br /><applet load="1ash" size="350" color="white" frame="true" align="right" spinBox="true" |
| - | <applet load="1ash" size=" | + | |
caption="1ash, resolution 2.15Å" /> | caption="1ash, resolution 2.15Å" /> | ||
'''THE STRUCTURE OF ASCARIS HEMOGLOBIN DOMAIN I AT 2.2 ANGSTROMS RESOLUTION: MOLECULAR FEATURES OF OXYGEN AVIDITY'''<br /> | '''THE STRUCTURE OF ASCARIS HEMOGLOBIN DOMAIN I AT 2.2 ANGSTROMS RESOLUTION: MOLECULAR FEATURES OF OXYGEN AVIDITY'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The perienteric hemoglobin of the parasitic nematode Ascaris has an | + | The perienteric hemoglobin of the parasitic nematode Ascaris has an exceptionally high affinity for oxygen. It is an octameric protein containing two similar heme-binding domains per subunit, but recombinant constructs expressing a single, monomeric heme-binding domain (domain 1; D1) retain full oxygen avidity. We have solved the crystal structure of D1 at 2.2 A resolution. Analysis of the structure reveals a characteristic globin fold and illuminates molecular features involved in oxygen avidity of Ascaris perienteric hemoglobin. A strong hydrogen bond between tyrosine at position 10 in the B helix (tyrosine-B10) and the distal oxygen of the ligand, combined with a weak hydrogen bond between glutamine-E7 and the proximal oxygen, grips the ligand in the binding pocket. A third hydrogen bond between these two amino acids appears to stabilize the structure. The B helix of D1 is displaced laterally by 2.5 A when compared with sperm whale myoglobin. This shifts the tyrosine-B10 hydroxyl far enough from liganded oxygen to form a strong hydrogen bond without steric hindrance. Changes in the F helix compared with myoglobin contribute to a tilted heme that may also be important for oxygen affinity. |
==About this Structure== | ==About this Structure== | ||
| - | 1ASH is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Ascaris_suum Ascaris suum] with HEM and OXY as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | + | 1ASH is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Ascaris_suum Ascaris suum] with <scene name='pdbligand=HEM:'>HEM</scene> and <scene name='pdbligand=OXY:'>OXY</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1ASH OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Ascaris suum]] | [[Category: Ascaris suum]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Goldberg, D | + | [[Category: Goldberg, D E.]] |
| - | [[Category: Kloek, A | + | [[Category: Kloek, A P.]] |
| - | [[Category: Mathews, F | + | [[Category: Mathews, F S.]] |
[[Category: Yang, J.]] | [[Category: Yang, J.]] | ||
[[Category: HEM]] | [[Category: HEM]] | ||
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[[Category: oxygen storage]] | [[Category: oxygen storage]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 11:47:53 2008'' |
Revision as of 09:47, 21 February 2008
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THE STRUCTURE OF ASCARIS HEMOGLOBIN DOMAIN I AT 2.2 ANGSTROMS RESOLUTION: MOLECULAR FEATURES OF OXYGEN AVIDITY
Overview
The perienteric hemoglobin of the parasitic nematode Ascaris has an exceptionally high affinity for oxygen. It is an octameric protein containing two similar heme-binding domains per subunit, but recombinant constructs expressing a single, monomeric heme-binding domain (domain 1; D1) retain full oxygen avidity. We have solved the crystal structure of D1 at 2.2 A resolution. Analysis of the structure reveals a characteristic globin fold and illuminates molecular features involved in oxygen avidity of Ascaris perienteric hemoglobin. A strong hydrogen bond between tyrosine at position 10 in the B helix (tyrosine-B10) and the distal oxygen of the ligand, combined with a weak hydrogen bond between glutamine-E7 and the proximal oxygen, grips the ligand in the binding pocket. A third hydrogen bond between these two amino acids appears to stabilize the structure. The B helix of D1 is displaced laterally by 2.5 A when compared with sperm whale myoglobin. This shifts the tyrosine-B10 hydroxyl far enough from liganded oxygen to form a strong hydrogen bond without steric hindrance. Changes in the F helix compared with myoglobin contribute to a tilted heme that may also be important for oxygen affinity.
About this Structure
1ASH is a Single protein structure of sequence from Ascaris suum with and as ligands. Full crystallographic information is available from OCA.
Reference
The structure of Ascaris hemoglobin domain I at 2.2 A resolution: molecular features of oxygen avidity., Yang J, Kloek AP, Goldberg DE, Mathews FS, Proc Natl Acad Sci U S A. 1995 May 9;92(10):4224-8. PMID:7753786
Page seeded by OCA on Thu Feb 21 11:47:53 2008
Categories: Ascaris suum | Single protein | Goldberg, D E. | Kloek, A P. | Mathews, F S. | Yang, J. | HEM | OXY | Oxygen storage
