View source for 4hbi


==SCAPHARCA DIMERIC HEMOGLOBIN, MUTANT T72I, DEOXY FORM==
<StructureSection load='4hbi' size='340' side='right'caption='[[4hbi]], [[Resolution|resolution]] 1.60&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4hbi]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Anadara_inaequivalvis Anadara inaequivalvis]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4HBI OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4HBI FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.6&#8491;</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></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=4hbi FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4hbi OCA], [https://pdbe.org/4hbi PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4hbi RCSB], [https://www.ebi.ac.uk/pdbsum/4hbi PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4hbi ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/GLB1_ANAIN GLB1_ANAIN] 
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/hb/4hbi_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=4hbi ConSurf].
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== Publication Abstract from PubMed ==
A cluster of interface ordered water molecules has been proposed to act as a key mediator of intersubunit communication in the homodimeric hemoglobin of Scapharca inaequivalvis. Mutations of Thr72 to Val and Ile, which lack the hydroxyl group to hydrogen bond the deoxy interface water molecules, result in sharply altered functional properties. We have determined the high resolution (1.6-1. 8 A) crystal structures of these two mutants in both the deoxygenated and CO-liganded states. These structures show minimal protein structural changes relative to the same native derivatives, despite greater than 40-fold increases in oxygen affinity. In the deoxy state of both mutants two water molecules at the periphery of the water cluster are lost, and the remaining cluster water molecules are destabilized. The CO-liganded structures show key differences between the two mutants including a more optimal interface packing involving Ile72 that acts to stabilize its high affinity (R) state. This additional stabilization allows rationalization of its lowered cooperativity within the context of a two-state model. These studies support a key role of ordered water in cooperative functioning and illustrate how subtle structural alterations can result in significantly altered functional properties in an allosteric molecule.

Mutational destabilization of the critical interface water cluster in Scapharca dimeric hemoglobin: structural basis for altered allosteric activity.,Pardanani A, Gambacurta A, Ascoli F, Royer WE Jr J Mol Biol. 1998 Dec 4;284(3):729-39. PMID:9826511<ref>PMID:9826511</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 4hbi" style="background-color:#fffaf0;"></div>

==See Also==
*[[Hemoglobin 3D structures|Hemoglobin 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Anadara inaequivalvis]]
[[Category: Large Structures]]
[[Category: Royer Junior WE]]