2y9h
From Proteopedia
STRUCTURE A OF CRISPR ENDORIBONUCLEASE CSE3 BOUND TO 19 NT RNA
Structural highlights
Function[Q53WG9_THET8] CRISPR (clustered regularly interspaced short palindromic repeat), is an adaptive immune system that provides protection against mobile genetic elements (viruses, transposable elements and conjugative plasmids). CRISPR clusters contain sequences complementary to antecedent mobile elements and target invading nucleic acids. CRISPR clusters are transcribed and processed into CRISPR RNA (crRNA). Processes pre-crRNA into individual crRNA units, but may not actually undergo enzyme turnover, retaining the crRNA product. Generates a 2',3'-cyclic phosphodiester.[1] [2] Publication Abstract from PubMedClustered 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. An RNA-induced conformational change required for CRISPR RNA cleavage by the endoribonuclease Cse3.,Sashital DG, Jinek M, Doudna JA Nat Struct Mol Biol. 2011 Jun;18(6):680-7. Epub 2011 May 15. PMID:21572442[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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