Csn2 is a Nmeni subtype-specific Cas protein, which may function in the adaptation process which mediates the incorporation of foreign nucleic acids into the microbial host genome. Csn 2 may interact directly with double-stranded DNA. CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) and associated Cas proteins comprise a system for heritable host defense by prokaryotic cells against phage and other foreign DNA. Csn2 has been predicted to be a functional analog of Cas4 based on anti-correlated phyletic patterns; also known as SPy1049 family.
Jiyao W et al.(2023). "The conserved domain database in 2023.",