Experimental Data Snapshot

  • Resolution: 1.90 Å
  • R-Value Free: 0.232 
  • R-Value Work: 0.208 
  • R-Value Observed: 0.208 

wwPDB Validation   3D Report Full Report

This is version 1.3 of the entry. See complete history


The T4 phage DNA mimic protein Arn inhibits the DNA binding activity of the bacterial histone-like protein H-NS

Ho, C.H.Wang, H.C.Ko, T.P.Chang, Y.C.Wang, A.H.J.

(2014) J Biol Chem 289: 27046-27054

  • DOI: https://doi.org/10.1074/jbc.M114.590851
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    The T4 phage protein Arn (Anti restriction nuclease) was identified as an inhibitor of the restriction enzyme McrBC. However, until now its molecular mechanism remained unclear. In the present study we used structural approaches to investigate biological properties of Arn. A structural analysis of Arn revealed that its shape and negative charge distribution are similar to dsDNA, suggesting that this protein could act as a DNA mimic. In a subsequent proteomic analysis, we found that the bacterial histone-like protein H-NS interacts with Arn, implying a new function. An electrophoretic mobility shift assay showed that Arn prevents H-NS from binding to the Escherichia coli hns and T4 p8.1 promoters. In vitro gene expression and electron microscopy analyses also indicated that Arn counteracts the gene-silencing effect of H-NS on a reporter gene. Because McrBC and H-NS both participate in the host defense system, our findings suggest that T4 Arn might knock down these mechanisms using its DNA mimicking properties.

  • Organizational Affiliation

    Institute of Biochemical Sciences, National Taiwan University, Taipei 106, Taiwan,; Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Anti-restriction endonuclease100Tequatrovirus T4Mutation(s): 0 
Gene Names: arnasiA.1motA.-6
Find proteins for P39510 (Enterobacteria phage T4)
Explore P39510 
Go to UniProtKB:  P39510
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP39510
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.90 Å
  • R-Value Free: 0.232 
  • R-Value Work: 0.208 
  • R-Value Observed: 0.208 
  • Space Group: H 3 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 81.959α = 90
b = 81.959β = 90
c = 149.424γ = 120
Software Package:
Software NamePurpose
Blu-Icedata collection
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

View Full Validation Report

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2014-08-20
    Type: Initial release
  • Version 1.1: 2014-12-10
    Changes: Database references
  • Version 1.2: 2017-11-22
    Changes: Refinement description
  • Version 1.3: 2024-03-20
    Changes: Data collection, Database references