Article

An RNA-induced conformational change required for CRISPR RNA cleavage by the endoribonuclease Cse3.

Department of Molecular and Cell Biology, University of California, Berkeley, California, USA.
Nature Structural &#38 Molecular Biology (impact factor: 12.71). 06/2011; 18(6):680-7. DOI:10.1038/nsmb.2043 pp.680-7
Source: PubMed

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.

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Keywords

adaptive immune system
 
catalytically essential RNA recognition mechanism
 
cleavage mechanisms
 
cleavage site
 
Cocrystal structures
 
cognate CRISPR RNA
 
CRISPR
 
CRISPR transcripts
 
CRISPR-associated
 
CRISPR-related endoRNases
 
CRISPR-specific endoRNases
 
Cse3 type CRISPR-specific endoRNases bind
 
Cse3-RNA complexes
 
enzyme active site
 
harbor sequences complementary
 
invasive nucleic acid elements
 
repetitive segment
 
RNA recognition
 
short RNA molecules
 
site-specific cleavage
 

Dipali G Sashital