Crystal structure of Ankyrin Repeat Domain of AKR2

Experimental Data Snapshot

  • Resolution: 2.30 Å
  • R-Value Free: 0.224 
  • R-Value Work: 0.206 
  • R-Value Observed: 0.207 

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An Ankyrin Repeat Domain of AKR2 Drives Chloroplast Targeting through Coincident Binding of Two Chloroplast Lipids.

Kim, D.H.Park, M.J.Gwon, G.H.Silkov, A.Xu, Z.Y.Yang, E.C.Song, S.Song, K.Kim, Y.Yoon, H.S.Honig, B.Cho, W.Cho, Y.Hwang, I.

(2014) Dev Cell 30: 598-609

  • DOI: https://doi.org/10.1016/j.devcel.2014.07.026
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    In organellogenesis of the chloroplast from endosymbiotic cyanobacteria, the establishment of protein-targeting mechanisms to the chloroplast should have been pivotal. However, it is still mysterious how these mechanisms were established and how they work in plant cells. Here we show that AKR2A, the cytosolic targeting factor for chloroplast outer membrane (COM) proteins, evolved from the ankyrin repeat domain (ARD) of the host cell by stepwise extensions of its N-terminal domain and that two lipids, monogalactosyldiacylglycerol (MGDG) and phosphatidylglycerol (PG), of the endosymbiont were selected to function as the AKR2A receptor. Structural analysis, molecular modeling, and mutational analysis of the ARD identified two adjacent sites for coincidental and synergistic binding of MGDG and PG. Based on these findings, we propose that the targeting mechanism of COM proteins was established using components from both the endosymbiont and host cell through a modification of the protein-protein-interacting ARD into a lipid binding domain.

  • Organizational Affiliation

    Division of Molecular and Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Korea.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Ankyrin repeat domain-containing protein 2
A, B, C, D, E
132Arabidopsis thalianaMutation(s): 0 
Gene Names: AKR2AFTAt4g35450F15J1.20
Find proteins for Q9SAR5 (Arabidopsis thaliana)
Explore Q9SAR5 
Go to UniProtKB:  Q9SAR5
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9SAR5
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.30 Å
  • R-Value Free: 0.224 
  • R-Value Work: 0.206 
  • R-Value Observed: 0.207 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 68.331α = 90
b = 59.381β = 107.33
c = 84.86γ = 90
Software Package:
Software NamePurpose

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2014-09-24
    Type: Initial release
  • Version 1.1: 2015-02-04
    Changes: Derived calculations
  • Version 1.2: 2023-12-27
    Changes: Data collection, Database references, Derived calculations, Other, Refinement description, Source and taxonomy