title: Sequence- and structure-specific RNA processing by a CRISPR endonuclease.
abstract: Many bacteria and archaea contain clustered regularly interspaced short palindromic repeats (CRISPRs) that confer resistance to invasive genetic elements. Central to this immune system is the production of CRISPR-derived RNAs (crRNAs) after transcription of the CRISPR locus. Here, we identify the endoribonuclease (Csy4) responsible for CRISPR transcript (pre-crRNA) processing in Pseudomonas aeruginosa. A 1.8 angstrom crystal structure of Csy4 bound to its cognate RNA reveals that Csy4 makes sequence-specific interactions in the major groove of the crRNA repeat stem-loop. Together with electrostatic contacts to the phosphate backbone, these enable Csy4 to bind selectively and cleave pre-crRNAs using phylogenetically conserved serine and histidine residues in the active site. The RNA recognition mechanism identified here explains sequence- and structure-specific processing by a large family of CRISPR-specific endoribonucleases.
authors.affiliation: Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA.
authors.forename: Rachel E
authors.initials: RE
authors.lastname: Haurwitz
authors.forename: Martin
authors.initials: M
authors.lastname: Jinek
authors.forename: Blake
authors.initials: B
authors.lastname: Wiedenheft
authors.forename: Kaihong
authors.initials: K
authors.lastname: Zhou
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Doudna
mesh_terms: D019943:Amino Acid Substitution; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism*; D020029:Base Pairing; D001483:Base Sequence; D064130:CRISPR-Associated Proteins; D003460:Crystallization; D018360:Crystallography, X-Ray; D004722:Endoribonucleases / Q000737:chemistry* / Q000378:metabolism*; D005798:Genes, Bacterial; D006860:Hydrogen Bonding; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D011550:Pseudomonas aeruginosa / Q000201:enzymology* / Q000235:genetics*; D012323:RNA Processing, Post-Transcriptional; D012329:RNA, Bacterial / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012091:Repetitive Sequences, Nucleic Acid; D055672:Static Electricity
chemical_list: D001426:Bacterial Proteins; D064130:CRISPR-Associated Proteins; D012329:RNA, Bacterial; C552242:Csy4 endoribonuclease, Pseudomonas aeruginosa; D004722:Endoribonucleases