title: An RNA-induced conformational change required for CRISPR RNA cleavage by the endoribonuclease Cse3.
abstract: Clustered regularly interspaced short palindromic repeat (CRISPR) chromosomal loci found in prokaryotes provide an adaptive immune system against bacteriophages and plasmids. CRISPR-specific endoRNases produce short RNA molecules (crRNAs) from CRISPR transcripts, which harbor sequences complementary to invasive nucleic acid elements and ensure their selective targeting by CRISPR-associated (Cas) proteins. The extreme sequence divergence of CRISPR-specific endoRNases and their RNA substrates has obscured homology-based comparison of RNA recognition and cleavage mechanisms. Here, we show that Cse3 type CRISPR-specific endoRNases bind a hairpin structure and residues downstream of the cleavage site within the repetitive segment of cognate CRISPR RNA. Cocrystal structures of Cse3-RNA complexes reveal an RNA-induced conformational change in the enzyme active site that aligns the RNA strand for site-specific cleavage. These studies provide insight into a catalytically essential RNA recognition mechanism by a large class of CRISPR-related endoRNases.
authors.affiliation: Department of Molecular and Cell Biology, University of California, Berkeley, California, USA.
authors.forename: Dipali G
authors.initials: DG
authors.lastname: Sashital
authors.forename: Martin
authors.initials: M
authors.lastname: Jinek
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Doudna
mesh_terms: D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D004722:Endoribonucleases / Q000737:chemistry* / Q000378:metabolism*; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D017434:Protein Structure, Tertiary; D012313:RNA / Q000737:chemistry* / Q000378:metabolism*; D016963:Thermus thermophilus / Q000737:chemistry / Q000201:enzymology*
chemical_list: D012313:RNA; D004722:Endoribonucleases