Structures of Cas9 endonucleases reveal RNA-mediated conformational activation

Science. 2014 Mar 14;343(6176):1247997. doi: 10.1126/science.1247997. Epub 2014 Feb 6.

Abstract

Type II CRISPR (clustered regularly interspaced short palindromic repeats)-Cas (CRISPR-associated) systems use an RNA-guided DNA endonuclease, Cas9, to generate double-strand breaks in invasive DNA during an adaptive bacterial immune response. Cas9 has been harnessed as a powerful tool for genome editing and gene regulation in many eukaryotic organisms. We report 2.6 and 2.2 angstrom resolution crystal structures of two major Cas9 enzyme subtypes, revealing the structural core shared by all Cas9 family members. The architectures of Cas9 enzymes define nucleic acid binding clefts, and single-particle electron microscopy reconstructions show that the two structural lobes harboring these clefts undergo guide RNA-induced reorientation to form a central channel where DNA substrates are bound. The observation that extensive structural rearrangements occur before target DNA duplex binding implicates guide RNA loading as a key step in Cas9 activation.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Actinomyces / enzymology*
  • Amino Acid Sequence
  • Bacterial Proteins / chemistry*
  • Clustered Regularly Interspaced Short Palindromic Repeats
  • Crystallography, X-Ray
  • DNA Cleavage
  • Endonucleases / chemistry*
  • Molecular Sequence Data
  • Nucleic Acid Conformation
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • RNA / chemistry*
  • Streptococcus pyogenes / enzymology*

Substances

  • Bacterial Proteins
  • RNA
  • Endonucleases

Associated data

  • PDB/4CMP
  • PDB/4CMQ
  • PDB/4OGC
  • PDB/4OGE