RloC is a distant homolog of the tRNALys anticodon nuclease (ACNase) [PrrC](/defense-systems/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 :ref{doi=10.1111/j.1365-2958.2008.06387.x}.
This system was not experimentally validated but is still considered as a defense system because of its homology with [PrrC](/defense-systems/prrc) and its abundance in [defense islands](/general-concepts/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) :ref{doi=10.1006/jmbi.1995.0343}. However, such activity was not directly shown on a phage
Zinc hook seems to regulate the nuclease function.
## Example of genomic structure
## Example of genomic structure
The RloC is composed of 1 protein: RloC.
The RloC is composed of 1 protein: RloC.
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## Experimental validation
## Experimental validation
<mermaid>
To our knowledge, there is no experimental validation for the RloC system.
graph LR;
Penner_1995[<ahref='https://doi.org/10.1006/jmbi.1995.0343'>Penner et al., 1995</a>] --> Origin_0