1y01: Difference between revisions
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[[Image:1y01.gif|left|200px]]<br /> | [[Image:1y01.gif|left|200px]]<br /><applet load="1y01" size="350" color="white" frame="true" align="right" spinBox="true" | ||
<applet load="1y01" size=" | |||
caption="1y01, resolution 2.8Å" /> | caption="1y01, resolution 2.8Å" /> | ||
'''Crystal structure of AHSP bound to Fe(II) alpha-hemoglobin'''<br /> | '''Crystal structure of AHSP bound to Fe(II) alpha-hemoglobin'''<br /> | ||
==Overview== | ==Overview== | ||
Hemoglobin A (HbA), the oxygen delivery system in humans, comprises two | Hemoglobin A (HbA), the oxygen delivery system in humans, comprises two alpha and two beta subunits. Free alpha-hemoglobin (alphaHb) is unstable, and its precipitation contributes to the pathophysiology of beta thalassemia. In erythrocytes, the alpha-hemoglobin stabilizing protein (AHSP) binds alphaHb and inhibits its precipitation. The crystal structure of AHSP bound to Fe(II)-alphaHb reveals that AHSP specifically recognizes the G and H helices of alphaHb through a hydrophobic interface that largely recapitulates the alpha1-beta1 interface of hemoglobin. The AHSP-alphaHb interactions are extensive but suboptimal, explaining why beta-hemoglobin can competitively displace AHSP to form HbA. Remarkably, the Fe(II)-heme group in AHSP bound alphaHb is coordinated by the distal but not the proximal histidine. Importantly, binding to AHSP facilitates the conversion of oxy-alphaHb to a deoxygenated, oxidized [Fe(III)], nonreactive form in which all six coordinate positions are occupied. These observations reveal the molecular mechanisms by which AHSP stabilizes free alphaHb. | ||
==Disease== | ==Disease== | ||
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==About this Structure== | ==About this Structure== | ||
1Y01 is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with HEM, OXY and CHK as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | 1Y01 is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with <scene name='pdbligand=HEM:'>HEM</scene>, <scene name='pdbligand=OXY:'>OXY</scene> and <scene name='pdbligand=CHK:'>CHK</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1Y01 OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Protein complex]] | [[Category: Protein complex]] | ||
[[Category: Feng, L.]] | [[Category: Feng, L.]] | ||
[[Category: Gell, D | [[Category: Gell, D A.]] | ||
[[Category: Gow, A | [[Category: Gow, A J.]] | ||
[[Category: Gu, L.]] | [[Category: Gu, L.]] | ||
[[Category: Mackay, J | [[Category: Mackay, J P.]] | ||
[[Category: Shi, Y.]] | [[Category: Shi, Y.]] | ||
[[Category: Weiss, M | [[Category: Weiss, M J.]] | ||
[[Category: Zhou, S.]] | [[Category: Zhou, S.]] | ||
[[Category: CHK]] | [[Category: CHK]] | ||
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[[Category: stabilization of alpha hemoglobin]] | [[Category: stabilization of alpha hemoglobin]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:00:26 2008'' | ||
