1DKE

NI BETA HEME HUMAN HEMOGLOBIN


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.10 Å
  • R-Value Free: 0.280 
  • R-Value Work: 0.200 
  • R-Value Observed: 0.200 

wwPDB Validation   3D Report Full Report


This is version 1.4 of the entry. See complete history


Literature

Oxygen binding by alpha(Fe2+)2beta(Ni2+)2 hemoglobin crystals.

Bruno, S.Bettati, S.Manfredini, M.Mozzarelli, A.Bolognesi, M.Deriu, D.Rosano, C.Tsuneshige, A.Yonetani, T.Henry, E.R.

(2000) Protein Sci 9: 683-692

  • DOI: 10.1110/ps.9.4.683
  • Primary Citation of Related Structures:  
    1DKE

  • PubMed Abstract: 
  • Oxygen binding by hemoglobin fixed in the T state either by crystallization or by encapsulation in silica gels is apparently noncooperative. However, cooperativity might be masked by different oxygen affinities of alpha and beta subunits. Metal hybrid hemoglobins, where the noniron metal does not bind oxygen, provide the opportunity to determine the oxygen affinities of alpha and beta hemes separately ...

    Oxygen binding by hemoglobin fixed in the T state either by crystallization or by encapsulation in silica gels is apparently noncooperative. However, cooperativity might be masked by different oxygen affinities of alpha and beta subunits. Metal hybrid hemoglobins, where the noniron metal does not bind oxygen, provide the opportunity to determine the oxygen affinities of alpha and beta hemes separately. Previous studies have characterized the oxygen binding by alpha(Ni2+)2beta(Fe2+)2 crystals. Here, we have determined the three-dimensional (3D) structure and oxygen binding of alpha(Fe2+)2beta(Ni2+)2 crystals grown from polyethylene glycol solutions. Polarized absorption spectra were recorded at different oxygen pressures with light polarized parallel either to the b or c crystal axis by single crystal microspectrophotometry. The oxygen pressures at 50% saturation (p50s) are 95 +/- 3 and 87 +/- 4 Torr along the b and c crystal axes, respectively, and the corresponding Hill coefficients are 0.96 +/- 0.06 and 0.90 +/- 0.03. Analysis of the binding curves, taking into account the different projections of the alpha hemes along the optical directions, indicates that the oxygen affinity of alpha1 hemes is 1.3-fold lower than alpha2 hemes. Inspection of the 3D structure suggests that this inequivalence may arise from packing interactions of the Hb tetramer within the monoclinic crystal lattice. A similar inequivalence was found for the beta subunits of alpha(Ni2+)2beta(Fe2+)2 crystals. The average oxygen affinity of the alpha subunits (p50 = 91 Torr) is about 1.2-fold higher than the beta subunits (p50 = 110 Torr). In the absence of cooperativity, this heterogeneity yields an oxygen binding curve of Hb A with a Hill coefficient of 0.999. Since the binding curves of Hb A crystals exhibit a Hill coefficient very close to unity, these findings indicate that oxygen binding by T-state hemoglobin is noncooperative, in keeping with the Monod, Wyman, and Changeux model.


    Organizational Affiliation

    Institute of Biochemical Sciences, University of Parma, Italy.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
HEMOGLOBIN: ALPHA CHAINAC141Homo sapiensMutation(s): 0 
Gene Names: HBA1HBA2
Find proteins for P69905 (Homo sapiens)
Explore P69905 
Go to UniProtKB:  P69905
NIH Common Fund Data Resources
PHAROS  P69905
Protein Feature View
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  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
HEMOGLOBIN: BETA CHAINBD146Homo sapiensMutation(s): 0 
Gene Names: HBB
Find proteins for P68871 (Homo sapiens)
Explore P68871 
Go to UniProtKB:  P68871
NIH Common Fund Data Resources
PHAROS  P68871
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
HEM
Query on HEM

Download CCD File 
A, B, C, D
PROTOPORPHYRIN IX CONTAINING FE
C34 H32 Fe N4 O4
KABFMIBPWCXCRK-RGGAHWMASA-L
 Ligand Interaction
SO4
Query on SO4

Download CCD File 
B
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.10 Å
  • R-Value Free: 0.280 
  • R-Value Work: 0.200 
  • R-Value Observed: 0.200 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 55.72α = 90
b = 81.4β = 97.81
c = 63.15γ = 90
Software Package:
Software NamePurpose
AMoREphasing
REFMACrefinement
MOSFLMdata reduction
CCP4data scaling
ROTAVATAdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2000-05-23
    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: 2017-10-04
    Changes: Advisory, Refinement description
  • Version 1.4: 2018-01-31
    Changes: Experimental preparation