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-Structure paper
Title | Structural insights into mechanisms of Argonaute protein-associated NADase activation in bacterial immunity. |
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Journal, issue, pages | Cell Res, Vol. 33, Issue 9, Page 699-711, Year 2023 |
Publish date | Jun 13, 2023 |
Authors | Xiaoshen Wang / Xuzichao Li / Guimei Yu / Lingling Zhang / Chendi Zhang / Yong Wang / Fumeng Liao / Yanan Wen / Hang Yin / Xiang Liu / Yong Wei / Zhuang Li / Zengqin Deng / Heng Zhang / |
PubMed Abstract | Nicotinamide adenine dinucleotide (NAD) is a central metabolite in cellular processes. Depletion of NAD has been demonstrated to be a prevalent theme in both prokaryotic and eukaryotic immune ...Nicotinamide adenine dinucleotide (NAD) is a central metabolite in cellular processes. Depletion of NAD has been demonstrated to be a prevalent theme in both prokaryotic and eukaryotic immune responses. Short prokaryotic Argonaute proteins (Agos) are associated with NADase domain-containing proteins (TIR-APAZ or SIR2-APAZ) encoded in the same operon. They confer immunity against mobile genetic elements, such as bacteriophages and plasmids, by inducing NAD depletion upon recognition of target nucleic acids. However, the molecular mechanisms underlying the activation of such prokaryotic NADase/Ago immune systems remain unknown. Here, we report multiple cryo-EM structures of NADase/Ago complexes from two distinct systems (TIR-APAZ/Ago and SIR2-APAZ/Ago). Target DNA binding triggers tetramerization of the TIR-APAZ/Ago complex by a cooperative self-assembly mechanism, while the heterodimeric SIR2-APAZ/Ago complex does not assemble into higher-order oligomers upon target DNA binding. However, the NADase activities of these two systems are unleashed via a similar closed-to-open transition of the catalytic pocket, albeit by different mechanisms. Furthermore, a functionally conserved sensor loop is employed to inspect the guide RNA-target DNA base pairing and facilitate the conformational rearrangement of Ago proteins required for the activation of these two systems. Overall, our study reveals the mechanistic diversity and similarity of Ago protein-associated NADase systems in prokaryotic immune response. |
External links | Cell Res / PubMed:37311833 / PubMed Central |
Methods | EM (single particle) |
Resolution | 3.0 - 3.7 Å |
Structure data | EMDB-35240, PDB-8i87: EMDB-35241, PDB-8i88: EMDB-35592, PDB-8in8: |
Chemicals | ChemComp-MG: |
Source |
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Keywords | ANTIVIRAL PROTEIN / a protein complex / VIRAL PROTEIN/ANTIVIRAL PROTEIN / VIRAL PROTEIN-ANTIVIRAL PROTEIN complex / a protein |