1YZI

A novel quaternary structure of human carbonmonoxy hemoglobin


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.07 Å
  • R-Value Free: 0.257 
  • R-Value Work: 0.208 
  • R-Value Observed: 0.208 

Starting Model: experimental
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Ligand Structure Quality Assessment 


This is version 1.4 of the entry. See complete history


Literature

The enigma of the liganded hemoglobin end state: a novel quaternary structure of human carbonmonoxy hemoglobin.

Safo, M.K.Abraham, D.J.

(2005) Biochemistry 44: 8347-8359

  • DOI: https://doi.org/10.1021/bi050412q
  • Primary Citation of Related Structures:  
    1MKO, 1YZI

  • PubMed Abstract: 

    The liganded hemoglobin (Hb) high-salt crystallization condition described by Max Perutz has generated three different crystals of human adult carbonmonoxy hemoglobin (COHbA). The first crystal is isomorphous with the "classical" liganded or R Hb structure. The second crystal reveals a new liganded Hb quaternary structure, RR2, that assumes an intermediate conformation between the R form and another liganded Hb quaternary structure, R2, which was discovered more than a decade ago. Like the R2 structure, the diagnostic R state hydrogen bond between beta2His97 and alpha1Thr38 is missing in the RR2 structure. The third crystal adopts a novel liganded Hb conformation, which we have termed R3, and it shows substantial quaternary structural differences from the R, RR2, and R2 structures. The quaternary structure differences between T and R3 are as large as those between T and R2; however, the T --> R3 and T --> R2 transitions are in different directions as defined by rigid-body screw rotation. Moreover, R3 represents an end state. Compared to all known liganded Hb structures, R3 shows remarkably reduced strain at the alpha-heme, reduced steric contact between the beta-heme ligand and the distal residues, smaller alpha- and beta-clefts, and reduced alpha1-alpha2 and beta1-beta2 iron-iron distances. Together, these unique structural features in R3 should make it the most relaxed and/or greatly enhance its affinity for oxygen compared to the other liganded Hbs. The current Hb structure-function relationships that are now based on T --> R, T -->R --> R2, or T --> R2 --> R transitions may have to be reexamined to take into account the RR2 and R3 liganded structures.


  • Organizational Affiliation

    School of Pharmacy, Department of Medicinal Chemistry, and Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, Virginia 23219, USA. msafo@mail2.vcu.edu


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Hemoglobin alpha chain141Homo 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 beta chain146Homo 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
Expand
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.07 Å
  • R-Value Free: 0.257 
  • R-Value Work: 0.208 
  • R-Value Observed: 0.208 
  • Space Group: P 41 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 61.464α = 90
b = 61.464β = 90
c = 174.75γ = 90
Software Package:
Software NamePurpose
CNSrefinement
bioteXdata reduction
CCP4data scaling
AMoREphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2005-03-15
    Type: Initial release
  • Version 1.1: 2008-04-30
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2017-10-11
    Changes: Refinement description
  • Version 1.4: 2023-08-23
    Changes: Data collection, Database references, Derived calculations, Refinement description