1GBU

DEOXY (BETA-(C93A,C112G)) HUMAN HEMOGLOBIN


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.8 Å
  • R-Value Work: 0.167 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Cysteines beta93 and beta112 as probes of conformational and functional events at the human hemoglobin subunit interfaces.

Vasquez, G.B.Karavitis, M.Ji, X.Pechik, I.Brinigar, W.S.Gilliland, G.L.Fronticelli, C.

(1999) Biophys.J. 76: 88-97

  • DOI: 10.1016/S0006-3495(99)77180-8
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Three variants of tetrameric human hemoglobin, with changes at the alpha1beta2/alpha2beta1-interface, at the alpha1beta1/alpha2beta2-interface, and at both interfaces, have been constructed. At alpha1beta2/alpha2beta1-interface the beta93 cysteine wa ...

    Three variants of tetrameric human hemoglobin, with changes at the alpha1beta2/alpha2beta1-interface, at the alpha1beta1/alpha2beta2-interface, and at both interfaces, have been constructed. At alpha1beta2/alpha2beta1-interface the beta93 cysteine was replaced by alanine (betaC93A), and at the alpha1beta1/alpha2beta2-interface the beta112 cysteine was replaced by glycine (betaC112G). The alpha1beta2 interface variant, betaC93A, and the alpha1beta1/alpha1beta2 double mutant, beta(C93A+C112G), were crystallized in the T-state, and the structures determined at 2. 0 and 1.8 A resolution, respectively. A comparison of the structures with that of natural hemoglobin A shows the absence of detectable changes in the tertiary folding of the protein or in the T-state quaternary assembly. At the beta112 site, the void left by the removal of the cysteine side chain is filled by a water molecule, and the functional characteristics of betaC112G are essentially those of human hemoglobin A. At the beta93 site, water molecules do not replace the cysteine side chain, and the alanine substitution increases the conformational freedom of beta146His, weakening the important interaction of this residue with beta94Asp. As a result, when Cl- is present in the solution, at a concentration 100 mM, the Bohr effect of the two mutants carrying the beta93Cys-->Ala substitution, betaC93A and beta(C93A+C112G), is significantly modified being practically absent below pH 7.4. Based on the crystallographic data, we attribute these effects to the competition between beta94Asp and Cl- in the salt link with beta146His in T-state hemoglobin. These results point to an interplay between the betaHis146-betaAsp94 salt bridge and the Cl- in solution regulated by the Cys present at position beta93, indicating yet another role of beta93 Cys in the regulation of hemoglobin function.


    Organizational Affiliation

    Center for Advanced Research in Biotechnology of the University of Maryland Biotechnology Institute and National Institute of Standards and Technology, Rockville, Maryland 20850, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
HEMOGLOBIN
A, C
141Homo sapiensGene 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
B, D
146Homo sapiensMutations: C93A, C112G
Gene Names: HBB
Find proteins for P68871 (Homo sapiens)
Go to Gene View: HBB
Go to UniProtKB:  P68871
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download SDF File 
Download CCD File 
B, D
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
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: 1.8 Å
  • R-Value Work: 0.167 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 63.020α = 90.00
b = 82.940β = 99.16
c = 53.830γ = 90.00
Software Package:
Software NamePurpose
PROLSQrefinement
XENGENdata reduction
GPRLSArefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1997-01-11
    Type: Initial release
  • Version 1.1: 2008-03-03
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance