3QQQ

Crystal structure of non-symbiotic plant hemoglobin from Trema tomentosa

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.84 Å
  • R-Value Free: 0.249 
  • R-Value Work: 0.213 
  • R-Value Observed: 0.215 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history. 


Literature

Crystal structures of Parasponia and Trema hemoglobins: differential heme coordination is linked to quaternary structure.

Kakar, S., Sturms, R., Tiffany, A., Nix, J.C., DiSpirito, A.A., Hargrove, M.S.

(2011) Biochemistry 50: 4273-4280

  • DOI: 10.1021/bi2002423
  • Primary Citation of Related Structures:  
    3QQQ, 3QQR

  • PubMed Abstract: 

    • Hemoglobins from the plants Parasponia andersonii (ParaHb) and Trema tomentosa (TremaHb) are 93% identical in primary structure but differ in oxygen binding constants in accordance with their distinct physiological functions. Additionally, these proteins are dimeric, and ParaHb exhibits the unusual property of having different heme redox potentials for each subunit ...

    Hemoglobins from the plants Parasponia andersonii (ParaHb) and Trema tomentosa (TremaHb) are 93% identical in primary structure but differ in oxygen binding constants in accordance with their distinct physiological functions. Additionally, these proteins are dimeric, and ParaHb exhibits the unusual property of having different heme redox potentials for each subunit. To investigate how these hemoglobins could differ in function despite their shared sequence identity and to determine the cause of subunit heterogeneity in ParaHb, we have measured their crystal structures in the ferric oxidation state. Furthermore, we have made a monomeric ParaHb mutant protein (I43N) and measured its ferrous/ferric heme redox potential to test the hypothesized link between quaternary structure and heme heterogeneity in wild-type ParaHb. Our results demonstrate that TremaHb is a symmetric dimeric hemoglobin similar to other class 1 nonsymbiotic plant hemoglobins but that ParaHb has structurally distinct heme coordination in each of its two subunits that is absent in the monomeric I43N mutant protein. A mechanism for achieving structural heterogeneity in ParaHb in which the Ile(101(F4)) side chain contacts the proximal His(105(F8)) in one subunit but not the other is proposed. These results are discussed in the context of the evolution of plant oxygen transport hemoglobins, and other potential functions of plant hemoglobins.

    Organizational Affiliation: 

    Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011, USA.



Macromolecules
Find similar proteins by: 
(by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Non-symbiotic hemoglobin A, B168Trema tomentosumMutation(s): 0 
Gene Names: GLB1
Find proteins for P07803 (Trema tomentosa)
Explore P07803 
Go to UniProtKB:  P07803
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
HEM
Query on HEM
Download Ideal Coordinates CCD File 
A, B
PROTOPORPHYRIN IX CONTAINING FE
C34 H32 Fe N4 O4
KABFMIBPWCXCRK-RGGAHWMASA-L		 Ligand Interaction
SO4
Query on SO4
Download Ideal Coordinates CCD File 
A, B
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L		 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.84 Å
  • R-Value Free: 0.249 
  • R-Value Work: 0.213 
  • R-Value Observed: 0.215 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 55.87α = 90
b = 70.736β = 90
c = 89.587γ = 90
Software Package:
Software NamePurpose
CrystalCleardata collection
SOLVEphasing
REFMACrefinement
d*TREKdata reduction
d*TREKdata scaling

Structure Validation

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View more in-depth experimental data

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2011-04-27
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2012-02-29
    Changes: Database references