STRUCTURAL BIOLOGY. A Cas9-guide RNA complex preorganized for target DNA recognition

Science. 2015 Jun 26;348(6242):1477-81. doi: 10.1126/science.aab1452.

Abstract

Bacterial adaptive immunity uses CRISPR (clustered regularly interspaced short palindromic repeats)-associated (Cas) proteins together with CRISPR transcripts for foreign DNA degradation. In type II CRISPR-Cas systems, activation of Cas9 endonuclease for DNA recognition upon guide RNA binding occurs by an unknown mechanism. Crystal structures of Cas9 bound to single-guide RNA reveal a conformation distinct from both the apo and DNA-bound states, in which the 10-nucleotide RNA "seed" sequence required for initial DNA interrogation is preordered in an A-form conformation. This segment of the guide RNA is essential for Cas9 to form a DNA recognition-competent structure that is poised to engage double-stranded DNA target sequences. We construe this as convergent evolution of a "seed" mechanism reminiscent of that used by Argonaute proteins during RNA interference in eukaryotes.

Publication types

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

MeSH terms

  • Argonaute Proteins / chemistry*
  • Bacterial Proteins / chemistry*
  • Bacterial Proteins / genetics
  • Base Sequence
  • CRISPR-Associated Protein 9
  • CRISPR-Cas Systems*
  • Clustered Regularly Interspaced Short Palindromic Repeats*
  • Crystallography, X-Ray
  • DNA / chemistry
  • DNA Cleavage*
  • Endonucleases / chemistry*
  • Endonucleases / genetics
  • Enzyme Activation
  • Evolution, Molecular
  • Molecular Sequence Data
  • Nucleic Acid Conformation
  • Protein Structure, Tertiary
  • RNA Interference
  • RNA, Guide / chemistry*
  • Streptococcus pyogenes / enzymology*

Substances

  • Argonaute Proteins
  • Bacterial Proteins
  • RNA, Guide
  • DNA
  • CRISPR-Associated Protein 9
  • Cas9 endonuclease Streptococcus pyogenes
  • Endonucleases

Associated data

  • PDB/4ZT0
  • PDB/4ZT9