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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 DOI10.2210/pdb6sh8/pdb
Related6S91
EMDB information10196
DescriptorCRISPR-associated protein, Cmr5 family, ZINC ION, PHOSPHOAMINOPHOSPHONIC ACID-ADENYLATE ESTER, ... (12 entities in total)
Functional Keywordscrispr-cas, effector complex, nuclease, cyclic oligo-adenylate synthase, antiviral protein
Biological sourceSulfolobus islandicus REY15A
More
Total number of polymer chains39
Total formula weight974077.80
Authors
Sofos, N.,Montoya, G.,Stella, S. (deposition date: 2019-08-06, release date: 2020-07-08, Last modification date: 2024-10-23)
Primary citationSofos, 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: 32730741
DOI: 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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