2HHE

OXYGEN AFFINITY MODULATION BY THE N-TERMINI OF THE BETA CHAINS IN HUMAN AND BOVINE HEMOGLOBIN


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.2 Å

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Chloride ion independence of the Bohr effect in a mutant human hemoglobin beta (V1M+H2deleted).

Fronticelli, C.Pechik, I.Brinigar, W.S.Kowalczyk, J.Gilliland, G.L.

(1994) J.Biol.Chem. 269: 23965-23969


  • PubMed Abstract: 
  • A mutant human hemoglobin, beta (V1M+H2 delta), has been constructed. Analysis of the oxygen binding curves obtained at pH 8.3, where the Bohr effect is inoperative, indicates that this mutation results in an additional stabilization of the T-state c ...

    A mutant human hemoglobin, beta (V1M+H2 delta), has been constructed. Analysis of the oxygen binding curves obtained at pH 8.3, where the Bohr effect is inoperative, indicates that this mutation results in an additional stabilization of the T-state conformation by 0.9 kcal/mol. The crystal structure of deoxy-beta (V1M+H2 delta) has been determined to 2.2-A resolution and compared with the deoxy structure of human hemoglobin at the same resolution. In human hemoglobin, a sulfate anion is anchored to the beta-chains by a complex network of H-bonds and electrostatic interactions with the amino terminus and Lys beta 82. In the mutant hemoglobin, the shortening of the amino-terminal region of the A helix by 1 residue results in the formation of an intrachain electrostatic interaction between the amino-terminal amino and Asp beta 79. This eliminates the sulfate binding site, and the sulfate is replaced by two water molecules. At variance with human hemoglobin, the alkaline Bohr effect for beta (V1M+H2 delta) is not sensitive to the presence of Cl-. This indicates that the sulfate binding site in human hemoglobin also serves as a Cl- binding site, and that the amino-terminal Val beta 1 is essential for oxygen-linked Cl- binding to hemoglobin as well as the Cl(-)-dependent Bohr effect. Analysis of the oxygen binding curves indicates that the oxygen-linked Cl- ions are released upon binding of the first oxygen molecule.


    Organizational Affiliation

    Department of Biochemistry, University of Maryland Medical School, Baltimore 21201.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
HEMOGLOBIN (DEOXY) (ALPHA CHAIN)
A, C
141Homo sapiensMutation(s): 0 
Gene Names: HBA1, HBA2
Find proteins for P69905 (Homo sapiens)
Go to Gene View: HBA1 HBA2
Go to UniProtKB:  P69905
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
HEMOGLOBIN (DEOXY) (BETA CHAIN)
B, D
145Homo sapiensMutation(s): 0 
Gene Names: HBB
Find proteins for P68871 (Homo sapiens)
Go to Gene View: HBB
Go to UniProtKB:  P68871
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
HEM
Query on HEM

Download SDF File 
Download CCD File 
A, B, C, D
PROTOPORPHYRIN IX CONTAINING FE
HEME
C34 H32 Fe N4 O4
KABFMIBPWCXCRK-RGGAHWMASA-L
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.2 Å
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 62.710α = 90.00
b = 82.380β = 99.21
c = 53.580γ = 90.00
Software Package:
Software NamePurpose
PROLSQrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1995-01-26
    Type: Initial release
  • Version 1.1: 2008-03-24
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance