8pcw

Structure of Csm6' from Streptococcus thermophilus

spinqualitylabelsall models 8pcw, resolution 3.54Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 8pcw is a 2 chain structure with sequence from Streptococcus thermophilus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 3.54Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function A0A0E2REG0_STRTR Publication Abstract from PubMed Type III CRISPR systems synthesize cyclic oligoadenylate (cOA) second messengers as part of a multi-faceted immune response against invading mobile genetic elements (MGEs). cOA activates non-specific CRISPR ancillary defence nucleases to create a hostile environment for MGE replication. Csm6 ribonucleases bind cOA using a CARF (CRISPR-associated Rossmann Fold) domain, resulting in activation of a fused HEPN (Higher Eukaryotes and Prokaryotes Nucleotide binding) ribonuclease domain. Csm6 enzymes are widely used in a new generation of diagnostic assays for the detection of specific nucleic acid species. However, the activation mechanism is not fully understood. Here we characterised the cyclic hexa-adenylate (cA6) activated Csm6' ribonuclease from the industrially important bacterium Streptococcus thermophilus. Crystal structures of Csm6' in the inactive and cA6 bound active states illuminate the conformational changes which trigger mRNA destruction. Upon binding of cA6, there is a close to 60 degrees rotation between the CARF and HEPN domains, which causes the 'jaws' of the HEPN domain to open and reposition active site residues. Key to this transition is the 6H domain, a right-handed solenoid domain connecting the CARF and HEPN domains, which transmits the conformational changes for activation. Activation of Csm6 ribonuclease by cyclic nucleotide binding: in an emergency, twist to open.,McQuarrie S, Athukoralage JS, McMahon SA, Graham S, Ackermann K, Bode BE, White MF, Gloster TM Nucleic Acids Res. 2023 Sep 25:gkad739. doi: 10.1093/nar/gkad739. PMID:37747760 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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