The structure of the karrikin insensitive (KAI2) protein in Arabidopsis thaliana

Experimental Data Snapshot

  • Resolution: 1.90 Å
  • R-Value Free: 0.174 
  • R-Value Work: 0.155 
  • R-Value Observed: 0.156 

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The Structure of the Karrikin-Insensitive Protein (KAI2) in Arabidopsis thaliana

Bythell-Douglas, R.Waters, M.T.Scaffidi, A.Flematti, G.R.Smith, S.M.Bond, C.S.

(2013) PLoS One 8: e54758-e54758

  • DOI: https://doi.org/10.1371/journal.pone.0054758
  • Primary Citation of Related Structures:  
    4HRX, 4HRY, 4HTA

  • PubMed Abstract: 

    KARRIKIN INSENSITIVE 2 (KAI2) is an α/β hydrolase involved in seed germination and seedling development. It is essential for plant responses to karrikins, a class of butenolide compounds derived from burnt plant material that are structurally similar to strigolactone plant hormones. The mechanistic basis for the function of KAI2 in plant development remains unclear. We have determined the crystal structure of Arabidopsis thaliana KAI2 in space groups P2(1) 2(1) 2(1) (a =63.57 Å, b =66.26 Å, c =78.25 Å) and P2(1) (a =50.20 Å, b =56.04 Å, c =52.43 Å, β =116.12°) to 1.55 and 2.11 Å respectively. The catalytic residues are positioned within a large hydrophobic pocket similar to that of DAD2, a protein required for strigolactone response in Petunia hybrida. KAI2 possesses a second solvent-accessible pocket, adjacent to the active site cavity, which offers the possibility of allosteric regulation. The structure of KAI2 is consistent with its designation as a serine hydrolase, as well as previous data implicating the protein in karrikin and strigolactone signalling.

  • Organizational Affiliation

    School of Chemistry and Biochemistry, The University of Western Australia, Crawley, WA, Australia.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Hydrolase, alpha/beta fold family protein288Arabidopsis thalianaMutation(s): 0 
Gene Names: F6G17.120AT4G37470
Find proteins for Q9SZU7 (Arabidopsis thaliana)
Explore Q9SZU7 
Go to UniProtKB:  Q9SZU7
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9SZU7
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.90 Å
  • R-Value Free: 0.174 
  • R-Value Work: 0.155 
  • R-Value Observed: 0.156 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 63.385α = 90
b = 66.064β = 90
c = 77.62γ = 90
Software Package:
Software NamePurpose
ADSCdata collection
XDSdata reduction
SCALAdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2013-02-27
    Type: Initial release
  • Version 1.1: 2024-03-20
    Changes: Data collection, Database references, Derived calculations