1QI8

DEOXYGENATED STRUCTURE OF A DISTAL POCKET HEMOGLOBIN MUTANT


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.80 Å
  • R-Value Free: 0.222 
  • R-Value Work: 0.169 

Starting Model: experimental
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This is version 1.3 of the entry. See complete history


Literature

Modulation of ligand binding in engineered human hemoglobin distal pocket.

Miele, A.E.Santanche, S.Travaglini-Allocatelli, C.Vallone, B.Brunori, M.Bellelli, A.

(1999) J Mol Biol 290: 515-524

  • DOI: https://doi.org/10.1006/jmbi.1999.2869
  • Primary Citation of Related Structures:  
    1QI8

  • PubMed Abstract: 

    Functional and structural studies on hemoglobin and myoglobin from different animals and engineered variants have enlightened the great importance of the physico-chemical properties of the side-chains at topological position B10 and E7. These residues proved to be crucial to the discrimination and stabilisation of gaseous ligands. In view of the data obtained on the high oxygen affinity hemoglobin from Ascaris worms and a new mutant of sperm whale myoglobin, we selected the two mutations Leu B10-->Tyr and His E7-->Gln as potentially relevant to control ligand binding parameters in the alpha and beta-chains of human hemoglobin. Here, we present an investigation of three new mutants: HbalphaYQ (alpha2YQbeta2A), HbbetaYQ (alpha2Abeta2YQ) and HbalphabetaYQ (alpha2YQbeta2YQ). They are characterised by a very low reactivity for NO, O2 and CO, and a reduced cooperativity. Their functional properties are not inconsistent with the behaviour expected for a two-state allosteric model. Proteins with these substitutions may be considered as candidates for the synthesis of a possible "blood substitute", which should yield an O2 adduct stable to autoxidation and slowly reacting with NO. The mutant HbalphabetaYQ is particularly interesting because the rate of reaction of NO with the oxy and deoxy derivatives is reduced. A structural interpretation of our data is presented based on the 3D structure of deoxy HbalphabetaYQ determined by crystallography at 1.8 A resolution.


  • Organizational Affiliation

    Department of Biochemical Sciences and C.N.R. Centre of Molecular Biology, University of Rome "La Sapienza", P.le A. Moro, 5, Rome, 00185, Italy.


Macromolecules
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Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
HEMOGLOBIN
A, C
141Homo sapiensMutation(s): 0 
UniProt & NIH Common Fund Data Resources
Find proteins for P69905 (Homo sapiens)
Explore P69905 
Go to UniProtKB:  P69905
PHAROS:  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
HEMOGLOBIN
B, D
146Homo sapiensMutation(s): 0 
UniProt & NIH Common Fund Data Resources
Find proteins for P68871 (Homo sapiens)
Explore P68871 
Go to UniProtKB:  P68871
PHAROS:  P68871
GTEx:  ENSG00000244734 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP68871
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.80 Å
  • R-Value Free: 0.222 
  • R-Value Work: 0.169 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 63.36α = 90
b = 94.32β = 99.43
c = 54γ = 90
Software Package:
Software NamePurpose
AMoREphasing
REFMACrefinement
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1999-07-11
    Type: Initial release
  • Version 1.1: 2008-04-26
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2023-08-16
    Changes: Data collection, Database references, Derived calculations, Refinement description