Structures of the CRISPR genome integration complex

Year: 2017

Type: article

Abstract: CRISPR-Cas systems depend on the Cas1-Cas2 integrase to capture and integrate short foreign DNA fragments into the CRISPR locus, enabling adaptation to new viruses. We present crystal structures of Cas1-Cas2 bound to both donor and target DNA in intermediate and product integration complexes, as well as a cryo-electron microscopy structure of the full CRISPR locus integration complex, including the accessory protein IHF (integration host factor). The structures show unexpectedly that indirect sequence recognition dictates integration site selection by favoring deformation of the repeat and the flanking sequences. IHF binding bends the DNA sharply, bringing an upstream recognition motif into contact with Cas1 to increase both the specificity and efficiency of integration. These results explain how the Cas1-Cas2 CRISPR integrase recognizes a sequence-dependent DNA structure to ensure site-selective CRISPR array expansion during the initial step of bacterial adaptive immunity.

Source: Science

DOI: 10.1126/science.aao0679

Authors: Addison V. Wright, Jun-Jie Liu, Gavin J. Knott, Kevin W. Doxzen, Eva Nogales, Jennifer A. Doudna

Institutions: University of California, Berkeley, Lawrence Berkeley National Laboratory, Howard Hughes Medical Institute, Innovative Genomics Institute

Language: English

Topic: CRISPR and Genetic Engineering

Subfield: Molecular Biology

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

Open Access status: green

Funders: National Science Foundation, Howard Hughes Medical Institute, U.S. Department of Energy, Sandler Foundation, National Institutes of Health, Office of Science, UC Berkeley College of Chemistry, Office of the President, University of California, National Institute of General Medical Sciences, Basic Energy Sciences, Biological and Environmental Research, SLAC National Accelerator Laboratory

OpenAlex ID: W2738807597