1ash: Difference between revisions
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[[Image:1ash.gif|left|200px]] | [[Image:1ash.gif|left|200px]] | ||
'''THE STRUCTURE OF ASCARIS HEMOGLOBIN DOMAIN I AT 2.2 ANGSTROMS RESOLUTION: MOLECULAR FEATURES OF OXYGEN AVIDITY''' | {{Structure | ||
|PDB= 1ash |SIZE=350|CAPTION= <scene name='initialview01'>1ash</scene>, resolution 2.15Å | |||
|SITE= | |||
|LIGAND= <scene name='pdbligand=HEM:PROTOPORPHYRIN+IX+CONTAINING+FE'>HEM</scene> and <scene name='pdbligand=OXY:OXYGEN MOLECULE'>OXY</scene> | |||
|ACTIVITY= | |||
|GENE= | |||
}} | |||
'''THE STRUCTURE OF ASCARIS HEMOGLOBIN DOMAIN I AT 2.2 ANGSTROMS RESOLUTION: MOLECULAR FEATURES OF OXYGEN AVIDITY''' | |||
==Overview== | ==Overview== | ||
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==About this Structure== | ==About this Structure== | ||
1ASH is a [ | 1ASH is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Ascaris_suum Ascaris suum]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1ASH OCA]. | ||
==Reference== | ==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:[http:// | 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:[http://www.ncbi.nlm.nih.gov/pubmed/7753786 7753786] | ||
[[Category: Ascaris suum]] | [[Category: Ascaris suum]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
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[[Category: oxygen storage]] | [[Category: oxygen storage]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Mar 20 10:01:43 2008'' | ||
Revision as of 08:01, 20 March 2008
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| 1ash, resolution 2.15Å | |||||||||||||
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| Ligands: | HEM and OXY | ||||||||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||||||||
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. 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
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