1r1x: Difference between revisions

Revision as of 06:58, 3 May 2008

Crystal structure of oxy-human hemoglobin Bassett at 2.15 angstrom

OverviewOverview

Hemoglobin (Hb) Bassett, an abnormal Hb variant with a markedly reduced oxygen affinity, was discovered in a Caucasian (Anglo-Saxon) male child who experienced episodes of cyanosis. Cation-exchange and reversed-phase (RP) high-performance liquid chromatography (HPLC) showed that the patient has an abnormal Hb, with a mutation in the alpha-globin. Tryptic peptide digest of the abnormal alpha-globin with subsequent HPLC analysis revealed abnormal elution of the alpha-T11 peptide. Further studies with Edman sequencing and electrospray mass spectrometry of tryptic peptide alpha-T11, as well as structural analysis by X-ray crystallography revealed an Asp-->Ala substitution at the alpha94 (G1) position, a match for Hb Bassett. Detailed functional studies showed that this Hb variant had a markedly reduced oxygen affinity (P(50) at pH 7.0 = 22 mmHg; Hb A P(50) = 10.5 mmHg), reduced Bohr effect (-0.26 compared to - 0.54 in Hb A), and low subunit cooperativity (n = 1.4, compared to 2.6 in Hb A). X-ray crystallography results explain the probable effects of the structural modification on the oxygen-binding properties of this Hb variant.

About this StructureAbout this Structure

1R1X is a Protein complex structure of sequences from Homo sapiens. Full crystallographic information is available from OCA.

ReferenceReference

Characterization of hemoglobin bassett (alpha94Asp-->Ala), a variant with very low oxygen affinity., Abdulmalik O, Safo MK, Lerner NB, Ochotorena J, Daikhin E, Lakka V, Santacroce R, Abraham DJ, Asakura T, Am J Hematol. 2004 Nov;77(3):268-76. PMID:15495251 Page seeded by OCA on Sat May 3 06:58:33 2008

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OCA

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 [[Image:1r1x.gif|left|200px]]
- {{Structure
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-}}
 '''Crystal structure of oxy-human hemoglobin Bassett at 2.15 angstrom'''
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 [[Category: Ochotorena, J.]]
 [[Category: Safo, M K.]]
-[[Category: carbon monoxide]]
+[[Category: Carbon monoxide]]
-[[Category: crystal structure]]
+[[Category: Crystal structure]]
-[[Category: hemoglobin]]
+[[Category: Hemoglobin]]
-[[Category: mutant]]
+[[Category: Mutant]]
-[[Category: oxygen affinity]]
+[[Category: Oxygen affinity]]
-[[Category: rochester]]
+[[Category: Rochester]]
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May  3 06:58:33 2008''
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 30 23:22:05 2008''