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; Cas1 is the most universal CRISPR system protein thought to be involved in spacer integration; Cas1 is metal-dependent deoxyribonuclease, also binds RNA; Shown to possess a unique fold consisting of a N-terminal beta-strand domain and a C-terminal alpha-helical domain
Jiyao W et al.(2023). "The conserved domain database in 2023.",