Crystal structure of Cas1 from Archaeoglobus fulgidus and its nucleolytic activity

Experimental Data Snapshot

  • Resolution: 2.40 Å
  • R-Value Free: 0.241 
  • R-Value Work: 0.199 
  • R-Value Observed: 0.201 

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Crystal structure of Cas1 from Archaeoglobus fulgidus and characterization of its nucleolytic activity

Kim, T.Y.Shin, M.Yen, L.H.T.Kim, J.S.

(2013) Biochem Biophys Res Commun 441: 720-725

  • DOI: https://doi.org/10.1016/j.bbrc.2013.10.122
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Clustered Regularly Interspaced Short Palindromic Repeats (CRISPRs) and CRISPR-associated (Cas) proteins are involved in bacterial acquired immunity against incoming hazardous genetic materials. Cas1 is ubiquitous in CRISPR-containing microorganisms and supposed to recognize and cleave a foreign nucleic acid, and integrate the cleaved fragment into host genome using a yet unidentified mechanism. However, all the reported Cas1s did not show the nucleolytic activity, which makes its role still obscure. The elucidated crystal structure of Cas1 from Archaeoglobus fulgidus (AfCas1) shows a butterfly-like dimeric structure. The Asp out of three confirmed nucleolytic residues of Glu, His, and Asp in other Cas1s is replaced with Glu in AfCas1. Further, insertion of five residues into one of two loops, which are close to the catalytic center of and disordered in other Cas1 structures, partially covers the active site of AfCas1. Nonetheless, in vitro assays show that its nucleic acid-binding activity was not impaired against the tested single-stranded (ss) DNA, various forms of double-stranded (ds) DNA, or ssRNA with a hydrolyzing activity against ssRNA and dsDNA in a metal ion-dependent way. These results support the proposed Cas1's function at the early step of this bacterial immune system.

  • Organizational Affiliation

    Department of Chemistry, Chonnam National University, Gwangju 500-757, Republic of Korea.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
CRISPR-associated endonuclease Cas1 1
A, B
347Archaeoglobus fulgidus DSM 4304Mutation(s): 0 
EC: 3.1
Find proteins for O28401 (Archaeoglobus fulgidus (strain ATCC 49558 / DSM 4304 / JCM 9628 / NBRC 100126 / VC-16))
Explore O28401 
Go to UniProtKB:  O28401
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupO28401
Sequence Annotations
  • Reference Sequence
Small Molecules
Modified Residues  1 Unique
IDChains TypeFormula2D DiagramParent
Query on MSE
A, B
Experimental Data & Validation

Experimental Data

  • Resolution: 2.40 Å
  • R-Value Free: 0.241 
  • R-Value Work: 0.199 
  • R-Value Observed: 0.201 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 70.886α = 90
b = 41.929β = 98.03
c = 125.293γ = 90
Software Package:
Software NamePurpose
HKL-2000data collection
HKL-2000data reduction
SCALAdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2014-01-15
    Type: Initial release