Download MendeleyCas1-Cas2 complex formation mediates spacer acquisition during CRISPR-Cas adaptive immunity.
Nunez, J.K., Kranzusch, P.J., Noeske, J., Wright, A.V., Davies, C.W., Doudna, J.A.(2014) Nat Struct Mol Biol 21: 528-534
- PubMed: 24793649
- DOI: https://doi.org/10.1038/nsmb.2820
- Primary Citation of Related Structures:
4P6I - PubMed 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.
Organizational Affiliation:
Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, USA.
