Crystal Structure of the Chloroplast Group II Intron Splicing Factor CRS2

Experimental Data Snapshot

  • Resolution: 1.70 Å
  • R-Value Free: 0.246 
  • R-Value Work: 0.173 
  • R-Value Observed: 0.176 

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Structural analysis of the group II intron splicing factor CRS2 yields insights into its protein and RNA interaction surfaces

Ostheimer, G.J.Hadjivasiliou, H.Kloer, D.P.Barkan, A.Matthews, B.W.

(2005) J Mol Biol 345: 51-68

  • DOI: https://doi.org/10.1016/j.jmb.2004.10.032
  • Primary Citation of Related Structures:  
    1RYB, 1RYM, 1RYN

  • PubMed Abstract: 

    Chloroplast RNA splicing 2 (CRS2) is a nuclear-encoded protein required for the splicing of nine group II introns in maize chloroplasts. CRS2 functions in the context of splicing complexes that include one of two CRS2-associated factors (CAF1 and CAF2). The CRS2-CAF1 and CRS2-CAF2 complexes are required for the splicing of different subsets of CRS2-dependent introns, and they bind tightly and specifically to their genetically defined intron targets in vivo. The CRS2 amino acid sequence is closely related to those of bacterial peptidyl-tRNA hydrolases (PTHs). To identify the structural differences between CRS2 and bacterial PTHs responsible for CRS2's gains of CAF binding and intron splicing functions, we determined the structure of CRS2 by X-ray crystallography. The fold of CRS2 is the same as that of Escherichia coli PTH, but CRS2 has two surfaces that differ from the corresponding surfaces in PTH. One of these is more hydrophobic in CRS2 than in PTH. Site-directed mutagenesis of this surface blocked CRS2-CAF complex formation, indicating that it is the CAF binding site. The CRS2 surface corresponding to the putative tRNA binding face of PTH is considerably more basic than in PTH, suggesting that CRS2 interacts with group II intron substrates via this surface. Both the sequence and the structural context of the amino acid residues essential for peptidyl-tRNA hydrolase activity are conserved in CRS2, yet expression of CRS2 is incapable of rescuing a pth(ts)E.coli strain.

  • Organizational Affiliation

    Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
CRS2205Zea maysMutation(s): 0 
Gene Names: crs2
Find proteins for Q9M5P4 (Zea mays)
Explore Q9M5P4 
Go to UniProtKB:  Q9M5P4
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9M5P4
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.70 Å
  • R-Value Free: 0.246 
  • R-Value Work: 0.173 
  • R-Value Observed: 0.176 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 36.375α = 90
b = 62.644β = 90
c = 78.235γ = 90
Software Package:
Software NamePurpose
MOSFLMdata reduction
SCALAdata scaling
CCP4data scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2003-12-30
    Type: Initial release
  • Version 1.1: 2008-04-29
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2023-08-23
    Changes: Data collection, Database references, Refinement description