Structure and mechanism of a Type III CRISPR defence DNA nuclease activated by cyclic oligoadenylate.

McMahon, Stephen A, Zhu, Wenlong ORCID: 0009-0002-6170-2201, Graham, Shirley ORCID: 0000-0002-2608-3815, Rambo, Robert ORCID: 0000-0003-2546-1615, White, Malcolm F ORCID: 0000-0003-1543-9342 and Gloster, Tracey M ORCID: 0000-0003-4692-2222 (2020) Structure and mechanism of a Type III CRISPR defence DNA nuclease activated by cyclic oligoadenylate. Nature communications, 11 (1). 500-.

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Official URL: http://dx.doi.org/10.1038/s41467-019-14222-x

Abstract

The CRISPR system provides adaptive immunity against mobile genetic elements in prokaryotes. On binding invading RNA species, Type III CRISPR systems generate cyclic oligoadenylate (cOA) signalling molecules, potentiating a powerful immune response by activating downstream effector proteins, leading to viral clearance, cell dormancy or death. Here we describe the structure and mechanism of a cOA-activated CRISPR defence DNA endonuclease, CRISPR ancillary nuclease 1 (Can1). Can1 has a unique monomeric structure with two CRISPR associated Rossman fold (CARF) domains and two DNA nuclease-like domains. The crystal structure of the enzyme has been captured in the activated state, with a cyclic tetra-adenylate (cA<sub>4</sub>) molecule bound at the core of the protein. cA<sub>4</sub> binding reorganises the structure to license a metal-dependent DNA nuclease activity specific for nicking of supercoiled DNA. DNA nicking by Can1 is predicted to slow down viral replication kinetics by leading to the collapse of DNA replication forks.

Item Type:	Article
Uncontrolled Keywords:	Thermus thermophilus, Endonucleases, DNA, Oligoribonucleotides, Adenine Nucleotides, Binding Sites, Structural Homology, Protein, Plasmids, Models, Molecular, Clustered Regularly Interspaced Short Palindromic Repeats, Protein Domains
Divisions:	Faculty of Health and Life Sciences Faculty of Health and Life Sciences > Institute of Systems, Molecular and Integrative Biology
Depositing User:	Symplectic Admin
Date Deposited:	18 Mar 2024 15:08
Last Modified:	18 Mar 2024 15:08
DOI:	10.1038/s41467-019-14222-x
Related URLs:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3179574