CRISPR (clustered regularly interspaced short palindromic repeat), is an adaptive immune system that provides protection against mobile genetic elements (viruses, transposable elements and conjugative plasmids). CRISPR clusters contain sequences complementary to antecedent mobile elements and target invading nucleic acids. CRISPR clusters are transcribed and processed into CRISPR RNA (crRNA), also called psiRNA (prokaryotic silencing) in this organism (Potential). Binds crRNA. Belongs to the CRISPR-associated protein Cas6/Cse3/CasE family. No in vitro nuclease activity has been observed against crRNA for this protein.