1BZ1

HEMOGLOBIN (ALPHA + MET) VARIANT


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.59 Å
  • R-Value Free: 0.224 
  • R-Value Work: 0.170 

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This is version 1.3 of the entry. See complete history


Literature

Structural and functional properties of human hemoglobins reassembled after synthesis in Escherichia coli.

Hui, H.L.Kavanaugh, J.S.Doyle, M.L.Wierzba, A.Rogers, P.H.Arnone, A.Holt, J.M.Ackers, G.K.Noble, R.W.

(1999) Biochemistry 38: 1040-1049

  • DOI: https://doi.org/10.1021/bi981986g
  • Primary Citation of Related Structures:  
    1BZ1, 1BZZ

  • PubMed Abstract: 

    Human hemoglobin produced in the Escherichia coli coexpression system of Hernan et al. [(1992) Biochemistry 31, 8619-8628] has been transformed into a functionally homogeneous protein whose properties closely approximate those of normal hemoglobin A. Both of the alpha and beta chains of this hemoglobin contain a valine-methionine substitution at position 1 in order to accommodate the difference in specificity of the protein-processing enzymes of procaryotes. Despite extensive purification, functional homogeneity of the E. coli expressed hemoglobin was achieved only by the complete disassembly of the hemoglobin into its component alpha and beta globins and their reassembly in the presence of hemin. The kinetics of CO combination and the thermodynamics of O2 binding and cooperativity of the reassembled alphaV1M-betaV1M hemoglobin closely approximate those of HbA. The alpha globin obtained from the E. coli expressed hemoglobin was also combined with normal human beta chains and hemin to form the alphaV1M variant. The alpha+M variant of HbA, in which the normal N-terminal valine of the alpha chains is preceded by a methionine residue, was prepared by the same procedure. The kinetics of the reactions of CO with the alphaV1M and alpha+M variants are similar to those for HbA. The equilibria of oxygen binding to alphaV1M and HbA are similar whereas alpha+M exhibits a significantly higher oxygen affinity. The three-dimensional structures of alphaV1M and alpha+M offer an explanation for the latter affinity difference. Although the structures of alphaV1M and HbA, which have been determined by X-ray crystallography, are virtually indistinguishable except at the N-terminal residues, that of alpha+M indicates the displacement of a solvent molecule, possibly a chloride ion, from arginine 141alpha. Such an alteration in an anion binding site could result in increased oxygen affinity.


  • Organizational Affiliation

    VA Medical Center, Department of Medicine, School of Medicine, University at Buffalo, New York 14215, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
PROTEIN (HEMOGLOBIN ALPHA CHAIN)
A, C
142Homo sapiensMutation(s): 0 
Gene Names: HUMAN ALPHA GLOBIN
UniProt & NIH Common Fund Data Resources
Find proteins for P69905 (Homo sapiens)
Explore P69905 
Go to UniProtKB:  P69905
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP69905
Sequence Annotations
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  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
PROTEIN (HEMOGLOBIN BETA CHAIN)
B, D
146Homo sapiensMutation(s): 0 
Gene Names: HUMAN ALPHA GLOBIN
UniProt & NIH Common Fund Data Resources
Find proteins for P68871 (Homo sapiens)
Explore P68871 
Go to UniProtKB:  P68871
GTEx:  ENSG00000244734 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP68871
Sequence Annotations
Expand
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.59 Å
  • R-Value Free: 0.224 
  • R-Value Work: 0.170 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 63.3α = 90
b = 83.6β = 99.4
c = 53.8γ = 90
Software Package:
Software NamePurpose
X-PLORmodel building
PROLSQrefinement
SDMSdata reduction
SDMSdata scaling
X-PLORphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1998-11-11
    Type: Initial release
  • Version 1.1: 2008-04-27
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2024-02-07
    Changes: Data collection, Database references, Derived calculations