PrrC
Description
The PrrC system protects bacteria against phages via an abortive infection. It is composed of a single effector protein but relies on the presence of a full type Ic restriction-modification system in the vicinity. PrrC proteins are therefore typically found embedded in a larger RM system.
Molecular mechanism
The effector protein prrC complements a RM system by cutting tRNALys in the anticodon loop, upstream of the wobble nucleotide and causes the arrest of phage protein synthesis and phage growth. PrrC serves as a guardian of the activity of EcoprrI, which can be inactivated by the Stp peptide of phage T4 at the beginning of infection. Inactivation of EcoprrI by Stp induces a conformation change that in turn activates PrrC, releasing its nuclease activity and stalling host and phage growth (N/A) . Because it sabotages the host's translation machinery, PrrC is considered to be an abortive infection system.
Example of genomic structure
The PrrC is composed of the PrrC protein and a type I restriction-modification system.
Here is an example found in the RefSeq database:
The PrrC system in Parazoarcus communis (GCF_003111645.1, NZ_CP022187) is composed of 4 proteins Type_I_REases (WP_108949925.1) Type_I_S (WP_108949926.1) PrrC (WP_108949927.1) Type_I_MTases (WP_108949929.1)