Structural biology. Crystal structure of a CRISPR RNA-guided surveillance complex bound to a ssDNA target.

Sabin Mulepati, Annie Héroux, Scott Bailey

Research output: Contribution to journalArticle

Abstract

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.

Original languageEnglish (US)
Pages (from-to)1479-1484
Number of pages6
JournalScience (New York, N.Y.)
Volume345
Issue number6203
DOIs
StatePublished - Sep 19 2014

ASJC Scopus subject areas

  • General

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