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; Cas3/Cas2 fusion; This protein includes both DEAH and HD motifs for helicase and N-terminal domain corresponding to Cas2 RNAse; signature gene for Type I and subtype I-F
Jiyao W et al.(2023). "The conserved domain database in 2023.",