|
Mode of Action (MoA)
|
ADP-ribosylates N250 of the Cas8f subunit, a residue required to recognise the PAM, within the crRNA-guided surveillance (Csy) complex.
|
|
Evidence
|
AcrIF11 was discovered as a widespread type I-F inhibitor. When ectopically expressed in P. aeruginosa strains with type I-F CRISPR targeting DMS3m (ECO_0000017), it allowed phage replication, indicating potent inhibition. Biochemical assays demonstrated that AcrIF11 catalyzes ADP-ribosylation of the Csy complex in the presence of NAD, specifically modifying residue N250 of the Cas8f subunit, a critical site for PAM recognition. This modification abolished the DNA binding ability of the Csy complex, confirmed through electrophoretic mobility shift assays (EMSA, ECO_0001807), mass spectrometry (ECO_0001096), and site-directed mutagenesis (e.g., Cas8f N250A). AcrIF11’s enzymatic activity required the presence of the Cas7.6f subunit for binding, and its NAD-binding and catalytic residues were essential for inhibition, as shown by in vitro cleavage and binding assays using catalytic mutants (ECO_0000015).
|
|
MoA Category
|
adds a post-translational modification and deactivates bacterial defence
|
|
Subtype(s) of the defence system(s) inhibited by the protein
Defence Subtype
|
Pseudomonas aeruginosa type I-F CRISPR-Cas
|
|
Relevant publication(s)
DOI
|
10.1126/science.aau5174,
10.1016/j.molcel.2020.09.015
|
|
Other components of the anti-defence system
Multicomponent System
|
-
|
|
Known structure in PDB
PDB ID
|
6KYF
|
|
Genome(s) encoding the protein
Protein Source
|
MGE in Pseudomonas aeruginosa
|
|
Defence system(s) inhibited by the protein
Defences
|
CRISPR-Cas
|