title: ArdA proteins from different mobile genetic elements can bind to the EcoKI Type I DNA methyltransferase of E. coli K12.
abstract: Anti-restriction and anti-modification (anti-RM) is the ability to prevent cleavage by DNA restriction-modification (RM) systems of foreign DNA entering a new bacterial host. The evolutionary consequence of anti-RM is the enhanced dissemination of mobile genetic elements. Homologues of ArdA anti-RM proteins are encoded by genes present in many mobile genetic elements such as conjugative plasmids and transposons within bacterial genomes. The ArdA proteins cause anti-RM by mimicking the DNA structure bound by Type I RM enzymes. We have investigated ArdA proteins from the genomes of Enterococcus faecalis V583, Staphylococcus aureus Mu50 and Bacteroides fragilis NCTC 9343, and compared them to the ArdA protein expressed by the conjugative transposon Tn916. We find that despite having very different structural stability and secondary structure content, they can all bind to the EcoKI methyltransferase, a core component of the EcoKI Type I RM system. This finding indicates that the less structured ArdA proteins become fully folded upon binding. The ability of ArdA from diverse mobile elements to inhibit Type I RM systems from other bacteria suggests that they are an advantage for transfer not only between closely-related bacteria but also between more distantly related bacterial species.
authors.affiliation: EaStCHEM School of Chemistry, The University of Edinburgh, The King's Buildings, Edinburgh EH9 3JJ, UK.
authors.forename: Kai
authors.initials: K
authors.lastname: Chen
authors.affiliation: EaStCHEM School of Chemistry, The University of Edinburgh, The King's Buildings, Edinburgh EH9 3JJ, UK.
authors.forename: Marcel
authors.initials: M
authors.lastname: Reuter
authors.affiliation: EaStCHEM School of Chemistry, The University of Edinburgh, The King's Buildings, Edinburgh EH9 3JJ, UK.
authors.forename: Bansi
authors.initials: B
authors.lastname: Sanghvi
authors.affiliation: EaStCHEM School of Chemistry, The University of Edinburgh, The King's Buildings, Edinburgh EH9 3JJ, UK.
authors.forename: Gareth A
authors.initials: GA
authors.lastname: Roberts
authors.affiliation: EaStCHEM School of Chemistry, The University of Edinburgh, The King's Buildings, Edinburgh EH9 3JJ, UK.
authors.forename: Laurie P
authors.initials: LP
authors.lastname: Cooper
authors.affiliation: EaStCHEM School of Chemistry, The University of Edinburgh, The King's Buildings, Edinburgh EH9 3JJ, UK.
authors.forename: Matthew
authors.initials: M
authors.lastname: Tilling
authors.affiliation: Institute of Cell Biology, School of Biological Sciences, The University of Edinburgh, The King's Buildings, Edinburgh EH9 3JR, UK.
authors.forename: Garry W
authors.initials: GW
authors.lastname: Blakely
authors.affiliation: EaStCHEM School of Chemistry, The University of Edinburgh, The King's Buildings, Edinburgh EH9 3JJ, UK.
authors.forename: David T F
authors.initials: DT
authors.lastname: Dryden
mesh_terms: D002850:Chromatography, Gel; D002942:Circular Dichroism; D048168:Escherichia coli K12 / Q000201:enzymology / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000378:metabolism*; D020071:Interspersed Repetitive Sequences; D008958:Models, Molecular; D011485:Protein Binding; D011489:Protein Denaturation; D017433:Protein Structure, Secondary; D012097:Repressor Proteins / Q000737:chemistry / Q000378:metabolism*; D015265:Site-Specific DNA-Methyltransferase (Adenine-Specific) / Q000378:metabolism*
chemical_list: C096738:ArdA protein, E coli; D029968:Escherichia coli Proteins; D012097:Repressor Proteins; C093244:DNA modification methylase EcoKI; D015265:Site-Specific DNA-Methyltransferase (Adenine-Specific)
keywords: ArdA protein; DNA methyltransferase; DNA mimic; Horizontal gene transfer