4AN8

Structure of Thermus thermophilus CasA (Cse1)


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.30 Å
  • R-Value Free: 0.247 
  • R-Value Work: 0.196 
  • R-Value Observed: 0.198 

wwPDB Validation   3D Report Full Report


This is version 1.1 of the entry. See complete history


Literature

Mechanism of Foreign DNA Selection in a Bacterial Adaptive Immune System.

Sashital, D.G.Wiedenheft, B.Doudna, J.A.

(2012) Mol Cell 46: 606

  • DOI: https://doi.org/10.1016/j.molcel.2012.03.020
  • Primary Citation of Related Structures:  
    4AN8

  • PubMed Abstract: 

    In bacterial and archaeal CRISPR immune pathways, DNA sequences from invading bacteriophage or plasmids are integrated into CRISPR loci within the host genome, conferring immunity against subsequent infections. The ribonucleoprotein complex Cascade utilizes RNAs generated from these loci to target complementary "nonself" DNA sequences for destruction, while avoiding binding to "self" sequences within the CRISPR locus. Here we show that CasA, the largest protein subunit of Cascade, is required for nonself target recognition and binding. Combining a 2.3 Å crystal structure of CasA with cryo-EM structures of Cascade, we have identified a loop that is required for viral defense. This loop contacts a conserved three base pair motif that is required for nonself target selection. Our data suggest a model in which the CasA loop scans DNA for this short motif prior to target destabilization and binding, maximizing the efficiency of DNA surveillance by Cascade.


  • Organizational Affiliation

    Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
CSE1
A, B
506Thermus thermophilus HB8Mutation(s): 0 
Gene Names: TTHB188
UniProt
Find proteins for Q53VY1 (Thermus thermophilus (strain ATCC 27634 / DSM 579 / HB8))
Explore Q53VY1 
Go to UniProtKB:  Q53VY1
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ53VY1
Sequence Annotations
Expand
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.30 Å
  • R-Value Free: 0.247 
  • R-Value Work: 0.196 
  • R-Value Observed: 0.198 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 94.36α = 90
b = 48.11β = 97.03
c = 129.78γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
XDSdata reduction
XSCALEdata scaling
autoSHARPphasing

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2012-05-02
    Type: Initial release
  • Version 1.1: 2012-06-20
    Changes: Other