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Title | The CRISPR-associated adenosine deaminase Cad1 converts ATP to ITP to provide antiviral immunity. |
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Journal, issue, pages | Cell, Vol. 187, Issue 25, Page 7183-7195.e24, Year 2024 |
Publish date | Dec 12, 2024 |
![]() | Christian F Baca / Puja Majumder / James H Hickling / Linzhi Ye / Marianna Teplova / Sean F Brady / Dinshaw J Patel / Luciano A Marraffini / ![]() |
PubMed Abstract | Type III CRISPR systems provide immunity against genetic invaders through the production of cyclic oligo-adenylate (cA) molecules that activate effector proteins that contain CRISPR-associated ...Type III CRISPR systems provide immunity against genetic invaders through the production of cyclic oligo-adenylate (cA) molecules that activate effector proteins that contain CRISPR-associated Rossman fold (CARF) domains. Here, we characterized the function and structure of an effector in which the CARF domain is fused to an adenosine deaminase domain, CRISPR-associated adenosine deaminase 1 (Cad1). We show that upon binding of cA or cA to its CARF domain, Cad1 converts ATP to ITP, both in vivo and in vitro. Cryoelectron microscopy (cryo-EM) structural studies on full-length Cad1 reveal an hexameric assembly composed of a trimer of dimers, with bound ATP at inter-domain sites required for activity and ATP/ITP within deaminase active sites. Upon synthesis of cA during phage infection, Cad1 activation leads to a growth arrest of the host that prevents viral propagation. Our findings reveal that CRISPR-Cas systems employ a wide range of molecular mechanisms beyond nucleic acid degradation to provide adaptive immunity in prokaryotes. |
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Methods | EM (single particle) / X-ray diffraction |
Resolution | 1.82 - 3.6 Å |
Structure data | EMDB-45241, PDB-9c67: EMDB-45244, PDB-9c6c: EMDB-45245, PDB-9c6f: EMDB-45277, PDB-9c77: EMDB-45466, PDB-9cdb: ![]() PDB-9c68: ![]() PDB-9c69: ![]() PDB-9c6a: |
Chemicals | ![]() ChemComp-MG: ![]() ChemComp-HOH: ![]() ChemComp-ATP: |
Source |
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![]() | ANTIVIRAL PROTEIN / Antiphage defense / CRISPR / Deamination / CARF-Adenosine deaminase / Antiviral Protein/RNA / Type-III CRISPR defense system / CARF-effector protein / adaptive immunity / deamination defense strategy / cyclic Hexa-adenylate / Antiviral Protein-RNA complex / CYTOSOLIC PROTEIN / cyclic Tetra-adenylate / ATP / cA4 |