1i3d: Difference between revisions
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< | ==HUMAN CARBONMONOXY HEMOGLOBIN BART'S (GAMMA4)== | ||
<StructureSection load='1i3d' size='340' side='right'caption='[[1i3d]], [[Resolution|resolution]] 1.70Å' scene=''> | |||
You may | == Structural highlights == | ||
<table><tr><td colspan='2'>[[1i3d]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1I3D OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1I3D 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]] 1.7Å</td></tr> | |||
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CMO:CARBON+MONOXIDE'>CMO</scene>, <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=1i3d FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1i3d OCA], [https://pdbe.org/1i3d PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1i3d RCSB], [https://www.ebi.ac.uk/pdbsum/1i3d PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1i3d ProSAT]</span></td></tr> | |||
</table> | |||
== Function == | |||
[https://www.uniprot.org/uniprot/HBG1_HUMAN HBG1_HUMAN] Gamma chains make up the fetal hemoglobin F, in combination with alpha chains. | |||
== 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/i3/1i3d_consurf.spt"</scriptWhenChecked> | |||
<scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.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=1i3d ConSurf]. | |||
<div style="clear:both"></div> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
Hemoglobin (Hb) Bart's is present in the red blood cells of millions of people worldwide who suffer from alpha-thalassemia. alpha-Thalassemia is a disease in which there is a deletion of one or more of the four alpha-chain genes, and excess gamma and beta chains spontaneously form homotetramers. The gamma(4) homotetrameric protein known as Hb Bart's is a stable species that exhibits neither a Bohr effect nor heme-heme cooperativity. Although Hb Bart's has a higher O(2) affinity than either adult (alpha(2)beta(2)) or fetal (alpha(2)gamma(2)) Hbs, it has a lower affinity for O(2) than HbH (beta(4)). To better understand the association and ligand binding properties of the gamma(4) tetramer, we have solved the structure of Hb Bart's in two different oxidation and ligation states. The crystal structure of ferrous carbonmonoxy (CO) Hb Bart's was determined by molecular replacement and refined at 1.7 A resolution (R = 21.1%, R(free) = 24.4%), and that of ferric azide (N(3)(-)) Hb Bart's was similarly determined at 1.86 A resolution (R = 18.4%, R(free) = 22.0%). In the carbonmonoxy-Hb structure, the CO ligand is bound at an angle of 140 degrees, and with an unusually long Fe-C bond of 2.25 A. This geometry is attributed to repulsion from the distal His63 at the low pH of crystallization (4.5). In contrast, azide is bound to the oxidized heme iron in the methemoglobin crystals at an angle of 112 degrees, in a perfect orientation to accept a hydrogen bond from His63. Compared to the three known quaternary structures of human Hb (T, R, and R2), both structures most closely resemble the R state. Comparisons with the structures of adult Hb and HbH explain the association and dissociation behaviour of Hb homotetramers relative to the heterotetrameric Hbs. | |||
Oligomerization and ligand binding in a homotetrameric hemoglobin: two high-resolution crystal structures of hemoglobin Bart's (gamma(4)), a marker for alpha-thalassemia.,Kidd RD, Baker HM, Mathews AJ, Brittain T, Baker EN Protein Sci. 2001 Sep;10(9):1739-49. PMID:11514664<ref>PMID:11514664</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
<div class="pdbe-citations 1i3d" style="background-color:#fffaf0;"></div> | |||
==See Also== | |||
*[[Hemoglobin 3D structures|Hemoglobin 3D structures]] | |||
== References == | |||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
== | |||
== | |||
[[Category: Homo sapiens]] | [[Category: Homo sapiens]] | ||
[[Category: | [[Category: Large Structures]] | ||
[[Category: Baker | [[Category: Baker EN]] | ||
[[Category: Baker | [[Category: Baker HM]] | ||
[[Category: Brittain | [[Category: Brittain T]] | ||
[[Category: Kidd | [[Category: Kidd RD]] | ||
[[Category: Mathews | [[Category: Mathews AJ]] | ||
Latest revision as of 09:20, 9 August 2023
HUMAN CARBONMONOXY HEMOGLOBIN BART'S (GAMMA4)HUMAN CARBONMONOXY HEMOGLOBIN BART'S (GAMMA4)
Structural highlights
FunctionHBG1_HUMAN Gamma chains make up the fetal hemoglobin F, in combination with alpha chains. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedHemoglobin (Hb) Bart's is present in the red blood cells of millions of people worldwide who suffer from alpha-thalassemia. alpha-Thalassemia is a disease in which there is a deletion of one or more of the four alpha-chain genes, and excess gamma and beta chains spontaneously form homotetramers. The gamma(4) homotetrameric protein known as Hb Bart's is a stable species that exhibits neither a Bohr effect nor heme-heme cooperativity. Although Hb Bart's has a higher O(2) affinity than either adult (alpha(2)beta(2)) or fetal (alpha(2)gamma(2)) Hbs, it has a lower affinity for O(2) than HbH (beta(4)). To better understand the association and ligand binding properties of the gamma(4) tetramer, we have solved the structure of Hb Bart's in two different oxidation and ligation states. The crystal structure of ferrous carbonmonoxy (CO) Hb Bart's was determined by molecular replacement and refined at 1.7 A resolution (R = 21.1%, R(free) = 24.4%), and that of ferric azide (N(3)(-)) Hb Bart's was similarly determined at 1.86 A resolution (R = 18.4%, R(free) = 22.0%). In the carbonmonoxy-Hb structure, the CO ligand is bound at an angle of 140 degrees, and with an unusually long Fe-C bond of 2.25 A. This geometry is attributed to repulsion from the distal His63 at the low pH of crystallization (4.5). In contrast, azide is bound to the oxidized heme iron in the methemoglobin crystals at an angle of 112 degrees, in a perfect orientation to accept a hydrogen bond from His63. Compared to the three known quaternary structures of human Hb (T, R, and R2), both structures most closely resemble the R state. Comparisons with the structures of adult Hb and HbH explain the association and dissociation behaviour of Hb homotetramers relative to the heterotetrameric Hbs. Oligomerization and ligand binding in a homotetrameric hemoglobin: two high-resolution crystal structures of hemoglobin Bart's (gamma(4)), a marker for alpha-thalassemia.,Kidd RD, Baker HM, Mathews AJ, Brittain T, Baker EN Protein Sci. 2001 Sep;10(9):1739-49. PMID:11514664[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences |
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