6SH8
Cryo-EM structure of the Type III-B Cmr-beta bound to cognate target RNA and AMPPnP, state 2, in the presence of ssDNA
Summary for 6SH8
Entry DOI | 10.2210/pdb6sh8/pdb |
Related | 6S91 |
EMDB information | 10196 |
Descriptor | CRISPR-associated protein, Cmr5 family, ZINC ION, PHOSPHOAMINOPHOSPHONIC ACID-ADENYLATE ESTER, ... (12 entities in total) |
Functional Keywords | crispr-cas, effector complex, nuclease, cyclic oligo-adenylate synthase, antiviral protein |
Biological source | Sulfolobus islandicus REY15A More |
Total number of polymer chains | 39 |
Total formula weight | 974077.80 |
Authors | Sofos, N.,Montoya, G.,Stella, S. (deposition date: 2019-08-06, release date: 2020-07-08, Last modification date: 2024-10-23) |
Primary citation | Sofos, N.,Feng, M.,Stella, S.,Pape, T.,Fuglsang, A.,Lin, J.,Huang, Q.,Li, Y.,She, Q.,Montoya, G. Structures of the Cmr-beta Complex Reveal the Regulation of the Immunity Mechanism of Type III-B CRISPR-Cas. Mol.Cell, 79:741-757.e7, 2020 Cited by PubMed Abstract: Cmr-β is a type III-B CRISPR-Cas complex that, upon target RNA recognition, unleashes a multifaceted immune response against invading genetic elements, including single-stranded DNA (ssDNA) cleavage, cyclic oligoadenylate synthesis, and also a unique UA-specific single-stranded RNA (ssRNA) hydrolysis by the Cmr2 subunit. Here, we present the structure-function relationship of Cmr-β, unveiling how binding of the target RNA regulates the Cmr2 activities. Cryoelectron microscopy (cryo-EM) analysis revealed the unique subunit architecture of Cmr-β and captured the complex in different conformational stages of the immune response, including the non-cognate and cognate target-RNA-bound complexes. The binding of the target RNA induces a conformational change of Cmr2, which together with the complementation between the 5' tag in the CRISPR RNAs (crRNA) and the 3' antitag of the target RNA activate different configurations in a unique loop of the Cmr3 subunit, which acts as an allosteric sensor signaling the self- versus non-self-recognition. These findings highlight the diverse defense strategies of type III complexes. PubMed: 32730741DOI: 10.1016/j.molcel.2020.07.008 PDB entries with the same primary citation |
Experimental method | ELECTRON MICROSCOPY (3.14 Å) |
Structure validation
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