BrxU, GmrSD-family Type IV restriction enzyme

Experimental Data Snapshot

  • Resolution: 2.12 Å
  • R-Value Free: 0.252 
  • R-Value Work: 0.204 
  • R-Value Observed: 0.206 

wwPDB Validation   3D Report Full Report

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The phage defence island of a multidrug resistant plasmid uses both BREX and type IV restriction for complementary protection from viruses.

Picton, D.M.Luyten, Y.A.Morgan, R.D.Nelson, A.Smith, D.L.Dryden, D.T.F.Hinton, J.C.D.Blower, T.R.

(2021) Nucleic Acids Res 49: 11257-11273

  • DOI: https://doi.org/10.1093/nar/gkab906
  • Primary Citation of Related Structures:  
    7P9K, 7P9M

  • PubMed Abstract: 

    Bacteria have evolved a multitude of systems to prevent invasion by bacteriophages and other mobile genetic elements. Comparative genomics suggests that genes encoding bacterial defence mechanisms are often clustered in 'defence islands', providing a concerted level of protection against a wider range of attackers. However, there is a comparative paucity of information on functional interplay between multiple defence systems. Here, we have functionally characterised a defence island from a multidrug resistant plasmid of the emerging pathogen Escherichia fergusonii. Using a suite of thirty environmentally-isolated coliphages, we demonstrate multi-layered and robust phage protection provided by a plasmid-encoded defence island that expresses both a type I BREX system and the novel GmrSD-family type IV DNA modification-dependent restriction enzyme, BrxU. We present the structure of BrxU to 2.12 Å, the first structure of the GmrSD family of enzymes, and show that BrxU can utilise all common nucleotides and a wide selection of metals to cleave a range of modified DNAs. Additionally, BrxU undergoes a multi-step reaction cycle instigated by an unexpected ATP-dependent shift from an intertwined dimer to monomers. This direct evidence that bacterial defence islands can mediate complementary layers of phage protection enhances our understanding of the ever-expanding nature of phage-bacterial interactions.

  • Organizational Affiliation

    Department of Biosciences, Durham University, Stockton Road, Durham DH1 3LE, UK.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
DUF262 domain-containing protein
A, B
587Escherichia fergusonii ATCC 35469Mutation(s): 0 
Gene Names: EFER_p0024
Find proteins for B7L3S9 (Escherichia fergusonii (strain ATCC 35469 / DSM 13698 / CCUG 18766 / IAM 14443 / JCM 21226 / LMG 7866 / NBRC 102419 / NCTC 12128 / CDC 0568-73))
Explore B7L3S9 
Go to UniProtKB:  B7L3S9
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupB7L3S9
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.12 Å
  • R-Value Free: 0.252 
  • R-Value Work: 0.204 
  • R-Value Observed: 0.206 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 214.62α = 90
b = 67.256β = 102.049
c = 126.547γ = 90
Software Package:
Software NamePurpose
DIALSdata reduction
DIALSdata scaling

Structure Validation

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Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
Biotechnology and Biological Sciences Research Council (BBSRC)United KingdomBB/M011186/1
Other privateUnited KingdomLister Insitute of Preventative Medicine Prize Fellowship

Revision History  (Full details and data files)

  • Version 1.0: 2021-12-08
    Type: Initial release
  • Version 1.1: 2024-03-20
    Changes: Data collection, Structure summary