In Type I and III CRISPR/Cas systems, the Cas6 family of endoribonucleases generates functional CRISPR-derived RNAs by site-specific cleavage of repeat sequences in precursor transcripts. The structure of Cas6 [1] showed it adopts a tandem ferredoxin/RRM fold. This entry represents the N-terminal domain.

1: Evolution of CRISPR RNA recognition and processing by Cas6 endonucleases. Niewoehner O, Jinek M, Doudna JA; Nucleic Acids Res. 2014;42:1341-1353. PMID:24150936