Ardc, proteína antirestricción que amplía el rango de huésped del plásmido

Résumé

Plasmids, when transferred by conjugation, have to overpass barrier controls such as the restriction-modification systems of the recipient cell, responsible for distinguishing between foreign and own DNA. Some conjugative plasmids encode their own antirestriction proteins, allowing the plasmids to overcome these barriers. ArdC, encoded by a gene of R388 broad host range plasmid, is required in the recipient cells for conjugation from Escherichia coli to Pseudomonas putida. We have solved the structure of ArdC, a protein composed of a non-specific ssDNA binding N-terminal domain and a C-terminal metalloprotease domain, although the metalloprotease activity is not needed for the DNA protective activity. We also report how ardC is not required for conjugation if Type I R-M system is depleted from P. putida recipient cells. Thus, ArdC has antirestriction activity against P. putida HsdRMS system broadening the R388 plasmid host range.