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-Structure paper
タイトル | An E1-E2 fusion protein primes antiviral immune signalling in bacteria. |
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ジャーナル・号・ページ | Nature, Vol. 616, Issue 7956, Page 319-325, Year 2023 |
掲載日 | 2023年2月8日 |
著者 | Hannah E Ledvina / Qiaozhen Ye / Yajie Gu / Ashley E Sullivan / Yun Quan / Rebecca K Lau / Huilin Zhou / Kevin D Corbett / Aaron T Whiteley / |
PubMed 要旨 | In all organisms, innate immune pathways sense infection and rapidly activate potent immune responses while avoiding inappropriate activation (autoimmunity). In humans, the innate immune receptor ...In all organisms, innate immune pathways sense infection and rapidly activate potent immune responses while avoiding inappropriate activation (autoimmunity). In humans, the innate immune receptor cyclic GMP-AMP synthase (cGAS) detects viral infection to produce the nucleotide second messenger cyclic GMP-AMP (cGAMP), which initiates stimulator of interferon genes (STING)-dependent antiviral signalling. Bacteria encode evolutionary predecessors of cGAS called cGAS/DncV-like nucleotidyltransferases (CD-NTases), which detect bacteriophage infection and produce diverse nucleotide second messengers. How bacterial CD-NTase activation is controlled remains unknown. Here we show that CD-NTase-associated protein 2 (Cap2) primes bacterial CD-NTases for activation through a ubiquitin transferase-like mechanism. A cryo-electron microscopy structure of the Cap2-CD-NTase complex reveals Cap2 as an all-in-one ubiquitin transferase-like protein, with distinct domains resembling eukaryotic E1 and E2 proteins. The structure captures a reactive-intermediate state with the CD-NTase C terminus positioned in the Cap2 E1 active site and conjugated to AMP. Cap2 conjugates the CD-NTase C terminus to a target molecule that primes the CD-NTase for increased cGAMP production. We further demonstrate that a specific endopeptidase, Cap3, balances Cap2 activity by cleaving CD-NTase-target conjugates. Our data demonstrate that bacteria control immune signalling using an ancient, minimized ubiquitin transferase-like system and provide insight into the evolution of the E1 and E2 machinery across domains of life. |
リンク | Nature / PubMed:36755092 / PubMed Central |
手法 | EM (単粒子) / X線回折 |
解像度 | 1.77 - 2.9 Å |
構造データ | EMDB-26028, PDB-7to3: EMDB-26066, PDB-7tqd: PDB-7tsq: PDB-7tsx: |
化合物 | ChemComp-AMP: ChemComp-MG: ChemComp-ATP: ChemComp-ADP: ChemComp-HOH: |
由来 |
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キーワード | TRANSFERASE / CBASS / ubiquitin E1/E2 / bacterial anti-phage defense / cGAS |