2W82

The structure of ArdA

Summary for 2W82

• Entry DOI: 10.2210/pdb2w82/pdb
• Descriptor: ORF18 (2 entities in total)
• Functional Keywords: dna mimic, replication inhibitor
• Biological source: ENTEROCOCCUS FAECALIS
• Total number of polymer chains: 4
• Total formula weight: 76543.53

Authors

McMahon, S.A.,Roberts, G.A.,Carter, L.G.,Cooper, L.P.,Liu, H.,White, J.H.,Johnson, K.A.,Sanghvi, B.,Oke, M.,Walkinshaw, M.D.,Blakely, G.,Naismith, J.H.,Dryden, D.T.F. (deposition date: 2009-01-08, release date: 2009-01-27, Last modification date: 2024-05-08)

Primary citation

Mcmahon, S.A.,Roberts, G.A.,Johnson, K.A.,Cooper, L.P.,Liu, H.,White, J.H.,Carter, L.G.,Sanghvi, B.,Oke, M.,Walkinshaw, M.D.,Blakely, G.,Naismith, J.H.,Dryden, D.T.F.
Extensive DNA Mimicry by the Arda Anti-Restriction Protein and its Role in the Spread of Antibiotic Resistance.
Nucleic Acids Res., 37:4887-, 2009

PubMed Abstract: The ardA gene, found in many prokaryotes including important pathogenic species, allows associated mobile genetic elements to evade the ubiquitous Type I DNA restriction systems and thereby assist the spread of resistance genes in bacterial populations. As such, ardA contributes to a major healthcare problem. We have solved the structure of the ArdA protein from the conjugative transposon Tn916 and find that it has a novel extremely elongated curved cylindrical structure with defined helical grooves. The high density of aspartate and glutamate residues on the surface follow a helical pattern and the whole protein mimics a 42-base pair stretch of B-form DNA making ArdA by far the largest DNA mimic known. Each monomer of this dimeric structure comprises three alpha-beta domains, each with a different fold. These domains have the same fold as previously determined proteins possessing entirely different functions. This DNA mimicry explains how ArdA can bind and inhibit the Type I restriction enzymes and we demonstrate that 6 different ardA from pathogenic bacteria can function in Escherichia coli hosting a range of different Type I restriction systems.

PubMed: 19506028
DOI: 10.1093/NAR/GKP478

Experimental method

X-RAY DIFFRACTION (2.8 Å)