1r1x

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Revision as of 11:10, 8 November 2007

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spinqualitylabelsall models 1r1x, resolution 2.15Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Crystal structure of oxy-human hemoglobin Bassett at 2.15 angstrom

Overview

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 Structure

1R1X is a Protein complex structure of sequences from Homo sapiens with CMO, HEM and MBN as ligands. Full crystallographic information is available from OCA.

Reference

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

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