6sce

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

spinqualitylabelsall models 6sce, resolution 1.83Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6sce is a 2 chain structure with sequence from Thermus thermophilus HB8 and Synthetic construct. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.83Å Ligands: MSE Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q53W14_THET8 Publication Abstract from PubMed 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 (cA4) molecule bound at the core of the protein. cA4 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. Structure and mechanism of a Type III CRISPR defence DNA nuclease activated by cyclic oligoadenylate.,McMahon SA, Zhu W, Graham S, Rambo R, White MF, Gloster TM Nat Commun. 2020 Jan 24;11(1):500. doi: 10.1038/s41467-019-14222-x. PMID:31980625 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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