3IA3

A cis-proline in alpha-hemoglobin stabilizing Protein directs the structural reorganization of alpha-hemoglobin


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.20 Å
  • R-Value Free: 0.293 
  • R-Value Work: 0.230 
  • R-Value Observed: 0.230 

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Ligand Structure Quality Assessment 


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Literature

A cis-proline in alpha-hemoglobin stabilizing protein directs the structural reorganization of alpha-hemoglobin.

Gell, D.A.Feng, L.Zhou, S.Jeffrey, P.D.Bendak, K.Gow, A.Weiss, M.J.Shi, Y.Mackay, J.P.

(2009) J Biol Chem 284: 29462-29469

  • DOI: 10.1074/jbc.M109.027045
  • Primary Citation of Related Structures:  
    3IA3

  • PubMed Abstract: 
  • alpha-Hemoglobin (alphaHb) stabilizing protein (AHSP) is expressed in erythropoietic tissues as an accessory factor in hemoglobin synthesis. AHSP forms a specific complex with alphaHb and suppresses the heme-catalyzed evolution of reactive oxygen species by converting alphaHb to a conformation in which the heme is coordinated at both axial positions by histidine side chains (bis-histidyl coordination) ...

    alpha-Hemoglobin (alphaHb) stabilizing protein (AHSP) is expressed in erythropoietic tissues as an accessory factor in hemoglobin synthesis. AHSP forms a specific complex with alphaHb and suppresses the heme-catalyzed evolution of reactive oxygen species by converting alphaHb to a conformation in which the heme is coordinated at both axial positions by histidine side chains (bis-histidyl coordination). Currently, the detailed mechanism by which AHSP induces structural changes in alphaHb has not been determined. Here, we present x-ray crystallography, NMR spectroscopy, and mutagenesis data that identify, for the first time, the importance of an evolutionarily conserved proline, Pro(30), in loop 1 of AHSP. Mutation of Pro(30) to a variety of residue types results in reduced ability to convert alphaHb. In complex with alphaHb, AHSP Pro(30) adopts a cis-peptidyl conformation and makes contact with the N terminus of helix G in alphaHb. Mutations that stabilize the cis-peptidyl conformation of free AHSP, also enhance the alphaHb conversion activity. These findings suggest that AHSP loop 1 can transmit structural changes to the heme pocket of alphaHb, and, more generally, highlight the importance of cis-peptidyl prolyl residues in defining the conformation of regulatory protein loops.


    Organizational Affiliation

    School of Molecular and Microbial Biosciences, University of Sydney, New South Wales 2006, Australia. dagell@mail.usyd.edu.au



Macromolecules
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Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Alpha-hemoglobin-stabilizing proteinA, C91Homo sapiensMutation(s): 0 
Gene Names: AHSPEDRFERAF
UniProt & NIH Common Fund Data Resources
Find proteins for Q9NZD4 (Homo sapiens)
Explore Q9NZD4 
Go to UniProtKB:  Q9NZD4
PHAROS:  Q9NZD4
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9NZD4
Protein Feature View
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  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
Hemoglobin subunit alphaB, D145Homo sapiensMutation(s): 0 
Gene Names: HBA1HBA2
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
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
HEM
Query on HEM

Download Ideal Coordinates CCD File 
E [auth B],
F [auth D]
PROTOPORPHYRIN IX CONTAINING FE
C34 H32 Fe N4 O4
KABFMIBPWCXCRK-RGGAHWMASA-L
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.20 Å
  • R-Value Free: 0.293 
  • R-Value Work: 0.230 
  • R-Value Observed: 0.230 
  • Space Group: P 61 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 65.23α = 90
b = 65.23β = 90
c = 439.66γ = 120
Software Package:
Software NamePurpose
CBASSdata collection
PHASERphasing
CNSrefinement
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2009-07-28
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance