Crystal Structure of a CRISPR RNA-guided Surveillance Complex Bound to a ssDNA Target
- Johns Hopkins Univ., Baltimore, MD (United States)
In prokaryotes, RNA derived from type I and type III CRISPR loci direct large ribonucleoprotein complexes to destroy invading bacteriophage and plasmids. In Escherichia coli, this 405-kilodalton complex is called Cascade. We report the crystal structure of Cascade bound to a single-stranded DNA (ssDNA) target at a resolution of 3.03 angstroms. The structure reveals that the CRISPR RNA and target strands do not form a double helix but instead adopt an underwound ribbon-like structure. This noncanonical structure is facilitated by rotation of every sixth nucleotide out of the RNA-DNA hybrid and is stabilized by the highly interlocked organization of protein subunits. These studies provide insight into both the assembly and the activity of this complex and suggest a mechanism to enforce fidelity of target binding.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- DOE Contract Number:
- SC00112704
- OSTI ID:
- 1228985
- Report Number(s):
- BNL-111060-2015-JA
- Journal Information:
- Science (New York, N.Y., Online), Vol. 345, Issue 6203; ISSN 1095-9203
- Country of Publication:
- United States
- Language:
- English
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