This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
1ash
From Proteopedia
| Line 4: | Line 4: | ||
|PDB= 1ash |SIZE=350|CAPTION= <scene name='initialview01'>1ash</scene>, resolution 2.15Å | |PDB= 1ash |SIZE=350|CAPTION= <scene name='initialview01'>1ash</scene>, resolution 2.15Å | ||
|SITE= | |SITE= | ||
| - | |LIGAND= <scene name='pdbligand=HEM:PROTOPORPHYRIN+IX+CONTAINING+FE'>HEM</scene> | + | |LIGAND= <scene name='pdbligand=HEM:PROTOPORPHYRIN+IX+CONTAINING+FE'>HEM</scene>, <scene name='pdbligand=OXY:OXYGEN+MOLECULE'>OXY</scene> |
|ACTIVITY= | |ACTIVITY= | ||
|GENE= | |GENE= | ||
| + | |DOMAIN= | ||
| + | |RELATEDENTRY= | ||
| + | |RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1ash FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1ash OCA], [http://www.ebi.ac.uk/pdbsum/1ash PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1ash RCSB]</span> | ||
}} | }} | ||
| Line 26: | Line 29: | ||
[[Category: Mathews, F S.]] | [[Category: Mathews, F S.]] | ||
[[Category: Yang, J.]] | [[Category: Yang, J.]] | ||
| - | [[Category: HEM]] | ||
| - | [[Category: OXY]] | ||
[[Category: oxygen storage]] | [[Category: oxygen storage]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 30 18:46:45 2008'' |
Revision as of 15:46, 30 March 2008
| |||||||
| , resolution 2.15Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | , | ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| 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
Page seeded by OCA on Sun Mar 30 18:46:45 2008
