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Title: Crystal Structure of a CRISPR RNA-guided Surveillance Complex Bound to a ssDNA Target

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.
Authors:
 [1] ; ;  [1]
  1. Johns Hopkins Univ., Baltimore, MD (United States)
Publication Date:
OSTI Identifier:
1228985
Report Number(s):
BNL--111060-2015-JA
Journal ID: ISSN 1095-9203
DOE Contract Number:
SC00112704
Resource Type:
Journal Article
Resource Relation:
Journal Name: Science (New York, N.Y., Online); Journal Volume: 345; Journal Issue: 6203
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES