Format

Send to

Choose Destination
See comment in PubMed Commons below
Nat Struct Mol Biol. 2014 Jun;21(6):528-34. doi: 10.1038/nsmb.2820. Epub 2014 May 4.

Cas1-Cas2 complex formation mediates spacer acquisition during CRISPR-Cas adaptive immunity.

Author information

1
Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, USA.
2
1] Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, USA. [2] Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, California, USA.
3
1] Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, USA. [2] Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, California, USA. [3] Department of Chemistry, University of California, Berkeley, Berkeley, California, USA. [4] Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA.

Abstract

The initial stage of CRISPR-Cas immunity involves the integration of foreign DNA spacer segments into the host genomic CRISPR locus. The nucleases Cas1 and Cas2 are the only proteins conserved among all CRISPR-Cas systems, yet the molecular functions of these proteins during immunity are unknown. Here we show that Cas1 and Cas2 from Escherichia coli form a stable complex that is essential for spacer acquisition and determine the 2.3-Å-resolution crystal structure of the Cas1-Cas2 complex. Mutations that perturb Cas1-Cas2 complex formation disrupt CRISPR DNA recognition and spacer acquisition in vivo. Active site mutants of Cas2, unlike those of Cas1, can still acquire new spacers, thus indicating a nonenzymatic role of Cas2 during immunity. These results reveal the universal roles of Cas1 and Cas2 and suggest a mechanism by which Cas1-Cas2 complexes specify sites of CRISPR spacer integration.

PMID:
24793649
PMCID:
PMC4075942
DOI:
10.1038/nsmb.2820
[Indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Nature Publishing Group Icon for PubMed Central
    Loading ...
    Support Center