The structural biology of CRISPR-Cas systems

• Published in: Current opinion in structural biology Vol. 30; pp. 100 - 111
• Main Authors: Jiang, Fuguo, Doudna, Jennifer A
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.02.2015
• Subjects: CRISPR-Associated Proteins - chemistry; CRISPR-Cas Systems - genetics; CRISPR-Cas Systems - physiology; Cryoelectron Microscopy; Crystallography, X-Ray; Escherichia coli; Gene Targeting - methods; Models, Molecular
• ISSN: 0959-440X; 1879-033X
• DOI: 10.1016/j.sbi.2015.02.002

•High-resolution Cascade structures provide a detailed view of Type I-E surveillance complex.•A working model is proposed to better understand Cascade-mediated DNA targeting and cleavage.•Type II CRISPR-Cas9 structures reveal insights into the mechanism of RNA-guided DNA targeting.•A model for PAM recognition and Cas9 activation is proposed. Prokaryotic CRISPR-Cas genomic loci encode RNA-mediated adaptive immune systems that bear some functional similarities with eukaryotic RNA interference. Acquired and heritable immunity against bacteriophage and plasmids begins with integration of ∼30 base pair foreign DNA sequences into the host genome. CRISPR-derived transcripts assemble with CRISPR-associated (Cas) proteins to target complementary nucleic acids for degradation. Here we review recent advances in the structural biology of these targeting complexes, with a focus on structural studies of the multisubunit Type I CRISPR RNA-guided surveillance and the Cas9 DNA endonuclease found in Type II CRISPR-Cas systems. These complexes have distinct structures that are each capable of site-specific double-stranded DNA binding and local helix unwinding.