CRISPR loci appear to be mobile elements with a wide host range. This entry represents a protein that tends to be found near CRISPR repeats. The species range for this species, so far, is exclusively archaeal. It is found so far in only four different species, and includes two tandem genes in Pyrococcus furiosus DSM 3638. CRISPR is a term for Clustered, Regularly Interspaced Short Palindromic Repeats. A number of protein families appear only in association with these repeats and are designated Cas (CRISPR-Associated) proteins.