|
Mode of Action (MoA)
|
ssDNA-binding protein with a metalloprotease domain; the mechanism is not clear.
|
|
Evidence
|
ArdC was identified as an anti-restriction factor that enhances plasmid conjugation across species barriers by counteracting Type I restriction-modification systems. Deletion of ardC (ECO_0007379) from plasmid R388 drastically reduced conjugation efficiency from E. coli to Pseudomonas putida, but not within E. coli, implicating a specific defense mechanism in P. putida. This effect was rescued by expressing ArdC (ECO_0000017) in the recipient cell, but not in the donor, confirming recipient-side activity. Conjugation into P. putida ΔhsdRMS mutants restored high transfer rates even without ArdC, directly implicating the HsdRMS restriction system as the target. A catalytically inactive ArdC mutant (E229A) retained full antirestriction function in conjugation assays, indicating that metalloprotease activity is dispensable and suggesting that DNA binding is the functional mechanism. RNA-seq analyses during ArdC-mediated conjugation revealed SOS response activation in recipient P. putida, likely due to increased ssDNA exposure. Together, these data establish ArdC as a recipient-expressed, ssDNA-binding antirestriction protein that enables plasmid transfer by protecting incoming DNA from HsdRMS degradation.
|
|
MoA Category
|
unknown
|
|
Subtype(s) of the defence system(s) inhibited by the protein
Defence Subtype
|
Pseudomonas putida type I RM (hsdRMS)
|
|
Relevant publication(s)
DOI
|
10.1371/journal.pgen.1008750
|
|
Other components of the anti-defence system
Multicomponent System
|
ardr;
arda;
ardk
|
|
Known structure in PDB
PDB ID
|
6SNA_A
|
|
Genome(s) encoding the protein
Protein Source
|
Plasmid R388
|
|
Defence system(s) inhibited by the protein
Defences
|
RM
|