7E2R

The ligand-free structure of Arabidopsis thaliana GUN4


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.30 Å
  • R-Value Free: 0.225 
  • R-Value Work: 0.195 
  • R-Value Observed: 0.196 

Starting Model: experimental
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wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Structural basis of bilin binding by the chlorophyll biosynthesis regulator GUN4.

Hu, J.H.Chang, J.W.Xu, T.Wang, J.Wang, X.Lin, R.Duanmu, D.Liu, L.

(2021) Protein Sci 30: 2083-2091

  • DOI: https://doi.org/10.1002/pro.4164
  • Primary Citation of Related Structures:  
    7E2R, 7E2S, 7E2T, 7E2U

  • PubMed Abstract: 

    The chlorophyll biosynthesis regulator GENOMES UNCOUPLED 4 (GUN4) is conserved in nearly all oxygenic photosynthetic organisms. Recently, GUN4 has been found to be able to bind the linear tetrapyrroles (bilins) and stimulate the magnesium chelatase activity in the unicellular green alga Chlamydomonas reinhardtii. Here, we characterize GUN4 proteins from Arabidopsis thaliana and the cyanobacterium Synechocystis sp. PCC 6803 for their ability to bind bilins, and present the crystal structures of Synechocystis GUN4 in biliverdin-bound, phycocyanobilin-bound, and phytochromobilin-bound forms at the resolutions of 1.05, 1.10, and 1.70 Å, respectively. These linear molecules adopt a cyclic-helical conformation, and bind more tightly than planar porphyrins to the tetrapyrrole-binding pocket of GUN4. Based on structural comparison, we propose a working model of GUN4 in regulation of tetrapyrrole biosynthetic pathway, and address the role of the bilin-bound GUN4 in retrograde signaling.


  • Organizational Affiliation

    School of Life Sciences, Anhui University, Hefei, China.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Tetrapyrrole-binding protein, chloroplastic
A, B
205Arabidopsis thalianaMutation(s): 0 
Gene Names: GUN4At3g59400F25L23_260
UniProt
Find proteins for Q9LX31 (Arabidopsis thaliana)
Explore Q9LX31 
Go to UniProtKB:  Q9LX31
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9LX31
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.30 Å
  • R-Value Free: 0.225 
  • R-Value Work: 0.195 
  • R-Value Observed: 0.196 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 47.758α = 90
b = 64.118β = 91.59
c = 55.705γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
HKL-2000data reduction
HKL-2000data scaling
PHASERphasing
PDB_EXTRACTdata extraction

Structure Validation

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Entry History & Funding Information

Deposition Data

  • Released Date: 2021-08-25 
  • Deposition Author(s): Liu, L., Hu, J.

Funding OrganizationLocationGrant Number
Ministry of Science and Technology (MoST, China)China2017YFA0503703

Revision History  (Full details and data files)

  • Version 1.0: 2021-08-25
    Type: Initial release
  • Version 1.1: 2022-02-16
    Changes: Database references
  • Version 1.2: 2023-11-29
    Changes: Data collection, Refinement description