1ash

<table><tr><td colspan='2'>[[1ash]] is a 1 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1ASH OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1ASH FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=HEM:PROTOPORPHYRIN+IX+CONTAINING+FE'>HEM</scene>, <scene name='pdbligand=OXY:OXYGEN+MOLECULE'>OXY</scene></td></tr>

[[https://www.uniprot.org/uniprot/GLB_ASCSU GLB_ASCSU]] Has an extremely high oxygen affinity. In a vacuum, it takes several minutes to release its oxygen compared to milliseconds for a normal globin. Could be used as an oxygen scavenger for sterol biosynthesis.

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== Publication Abstract from PubMed ==

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.

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<ref>PMID:7753786</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

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== References ==

<references/>

[[Category: Goldberg, D E]]

[[Category: Kloek, A P]]

[[Category: Mathews, F S]]

[[Category: Yang, J]]

[[Category: Oxygen storage]]