Publication Date:
2015-11-03
Description:
Cas9 is an RNA-guided DNA endonuclease that targets foreign DNA for destruction as part of a bacterial adaptive immune system mediated by clustered regularly interspaced short palindromic repeats (CRISPR). Together with single-guide RNAs, Cas9 also functions as a powerful genome engineering tool in plants and animals, and efforts are underway to increase the efficiency and specificity of DNA targeting for potential therapeutic applications. Studies of off-target effects have shown that DNA binding is far more promiscuous than DNA cleavage, yet the molecular cues that govern strand scission have not been elucidated. Here we show that the conformational state of the HNH nuclease domain directly controls DNA cleavage activity. Using intramolecular Forster resonance energy transfer experiments to detect relative orientations of the Cas9 catalytic domains when associated with on- and off-target DNA, we find that DNA cleavage efficiencies scale with the extent to which the HNH domain samples an activated conformation. We furthermore uncover a surprising mode of allosteric communication that ensures concerted firing of both Cas9 nuclease domains. Our results highlight a proofreading mechanism beyond initial protospacer adjacent motif (PAM) recognition and RNA-DNA base-pairing that serves as a final specificity checkpoint before DNA double-strand break formation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sternberg, Samuel H -- LaFrance, Benjamin -- Kaplan, Matias -- Doudna, Jennifer A -- T32GM007232/GM/NIGMS NIH HHS/ -- Howard Hughes Medical Institute/ -- England -- Nature. 2015 Nov 5;527(7576):110-3. doi: 10.1038/nature15544. Epub 2015 Oct 28.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University of California, Berkeley, California 94720, USA. ; Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA. ; Howard Hughes Medical Institute, University of California, Berkeley, California 94720, USA. ; Innovative Genomics Initiative, University of California, Berkeley, California 94720, USA. ; Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26524520" target="_blank"〉PubMed〈/a〉
Keywords:
Allosteric Regulation
;
Bacterial Proteins/chemistry/metabolism
;
Base Pairing
;
Binding Sites
;
CRISPR-Associated Proteins/*chemistry/*metabolism
;
*CRISPR-Cas Systems
;
Catalytic Domain
;
DNA/chemistry/*metabolism
;
DNA Breaks, Double-Stranded
;
*DNA Cleavage
;
Endonucleases/chemistry/*metabolism
;
Fluorescence Resonance Energy Transfer
;
*Genetic Engineering
;
Models, Molecular
;
RNA, Guide/chemistry/metabolism
;
Streptococcus pyogenes
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
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