CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) is a widespread family of prokaryotic direct repeats with spacers of unique sequence between consecutive repeats. This protein family is a CRISPR-associated (Cas) family strictly associated with the Cyano subtype of CRISPR/Cas locus, found in several species of Cyanobacteria and several archaeal species. It contains helicase motifs and appears to represent the Cas3 protein of the Cyano subtype of CRISPR/Cas system.
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