Contributors: Aude Bernheim, Florian Tesson


RloC is a distant homolog of the tRNALys anticodon nuclease (ACNase) PrrC. RloC shares the ABC ATPase motifs and catalytic ACNase triad with PrrC, but it possesses a unique zinc-hook/coiled-coil insert. This distinctive feature results in its ATPase domain bearing similarity to Rad50 and other DNA repair proteins.Contrary to PrrC RloC is rarely linked to a type I R-M system. RloC activity was not directly demonstrated on phages but hypothesized through its similar features to PrrC () .

This system was not experimentally validated but is still considered as a defense system because of its homology with PrrC and its abundance in defense islands. Of the RloC system detected by DefenseFinder around 40% are close to at least one known defense system (20 proteins on each side).

Molecular Mechanism

RloC was shown to function by tRNA cleavage (wobble nucleotide-excising and Zn++-responsive tRNase) () . However, such activity was not directly shown on a phage Zinc hook seems to regulate the nuclease function.

Example of genomic structure

The RloC is composed of 1 protein: RloC.

Here is an example found in the RefSeq database:

The RloC system in Pseudomonas aeruginosa (GCF_000981825.1, NZ_CP011317) is composed of 1 protein: RloC (WP_010794466.1)

Distribution of the system among prokaryotes

Among the 22,803 complete genomes of RefSeq, the RloC is detected in 1944 genomes (8.53 %).

The system was detected in 919 different species.

Proportion of genome encoding the RloC system for the 14 phyla with more than 50 genomes in the RefSeq database.



Example 1

Experimental validation

To our knowledge, there is no experimental validation for the RloC system.


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