4C0N

Crystal structure of non symbiotic plant hemoglobin AHb3 (GLB3) from Arabidopsis thaliana


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.77 Å
  • R-Value Free: 0.205 
  • R-Value Work: 0.186 
  • R-Value Observed: 0.187 

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This is version 1.1 of the entry. See complete history


Literature

The Structure of a Class 3 Nonsymbiotic Plant Haemoglobin from Arabidopsis Thaliana Reveals a Novel N-Terminal Helical Extension

Reeder, B.J.Hough, M.A.

(2014) Acta Crystallogr D Biol Crystallogr 70: 1411

  • DOI: 10.1107/S1399004714004878
  • Primary Citation of Related Structures:  
    4C0N

  • PubMed Abstract: 
  • Plant nonsymbiotic haemoglobins fall into three classes, each with distinct properties but all with largely unresolved physiological functions. Here, the first crystal structure of a class 3 nonsymbiotic plant haemoglobin, that from Arabidopsis thaliana, is reported to 1 ...

    Plant nonsymbiotic haemoglobins fall into three classes, each with distinct properties but all with largely unresolved physiological functions. Here, the first crystal structure of a class 3 nonsymbiotic plant haemoglobin, that from Arabidopsis thaliana, is reported to 1.77 Å resolution. The protein forms a homodimer, with each monomer containing a two-over-two α-helical domain similar to that observed in bacterial truncated haemoglobins. A novel N-terminal extension comprising two α-helices plays a major role in the dimer interface, which occupies the periphery of the dimer-dimer face, surrounding an open central cavity. The haem pocket contains a proximal histidine ligand and an open sixth iron-coordination site with potential for a ligand, in this structure hydroxide, to form hydrogen bonds to a tyrosine or a tryptophan residue. The haem pocket appears to be unusually open to the external environment, with another cavity spanning the entrance of the two haem pockets. The final 23 residues of the C-terminal domain are disordered in the structure; however, these domains in the functional dimer are adjacent and include the only two cysteine residues in the protein sequence. It is likely that these residues form disulfide bonds in vitro and it is conceivable that this C-terminal region may act in a putative complex with a partner molecule in vivo.


    Organizational Affiliation

    School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, Essex CO4 3SQ, England.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
2-ON-2 HEMOGLOBINA175Arabidopsis thalianaMutation(s): 0 
Gene Names: GLB3At4g32690F4D11.110
Find proteins for Q67XG0 (Arabidopsis thaliana)
Explore Q67XG0 
Go to UniProtKB:  Q67XG0
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
HEM
Query on HEM

Download CCD File 
A
PROTOPORPHYRIN IX CONTAINING FE
C34 H32 Fe N4 O4
KABFMIBPWCXCRK-RGGAHWMASA-L
 Ligand Interaction
CL
Query on CL

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A
CHLORIDE ION
Cl
VEXZGXHMUGYJMC-UHFFFAOYSA-M
 Ligand Interaction
OH
Query on OH

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A
HYDROXIDE ION
H O
XLYOFNOQVPJJNP-UHFFFAOYSA-M
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.77 Å
  • R-Value Free: 0.205 
  • R-Value Work: 0.186 
  • R-Value Observed: 0.187 
  • Space Group: P 43 3 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 123.373α = 90
b = 123.373β = 90
c = 123.373γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
MOSFLMdata reduction
SCALAdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2014-05-14
    Type: Initial release
  • Version 1.1: 2014-05-21
    Changes: Database references