Li Yutao, Li Zhaoxing, Yan Purui, Hua Chenyang, Kong Jianping, Wu Wanqian, Cui Yurong, Duan Yan, Li Shunxiang, Li Guanglei, Ji Shunli, Chen Yijun, Zhao Yucheng, Yang Peng, Hu Chunyi, Lu Meiling, Chen Meirong, Xiao Yibei
Department of Pharmacology, School of Pharmacy, China Pharmaceutical University, Nanjing, China.
State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China.
Science. 2025 Feb 21;387(6736):eadr0393. doi: 10.1126/science.adr0393.
Prokaryotes have evolved diverse defense strategies against viral infection, including foreign nucleic acid degradation by CRISPR-Cas systems and DNA and RNA synthesis inhibition through nucleotide pool depletion. Here, we report an antiviral mechanism of type III CRISPR-Cas-regulated adenosine triphosphate (ATP) depletion in which ATP is converted into inosine triphosphate (ITP) by CRISPR-Cas-associated adenosine deaminase (CAAD) upon activation by either cA or cA, followed by hydrolysis into inosine monophosphate (IMP) by Nudix hydrolase, ultimately resulting in cell growth arrest. The cryo-electron microscopy structures of CAAD in its apo and activated forms, together with biochemical evidence, revealed how cA or cA binds to the CRISPR-associated Rossmann fold (CARF) domain and abrogates CAAD autoinhibition, inducing substantial conformational changes that reshape the structure of CAAD and induce its deaminase activity. Our results reveal the mechanism of a CRISPR-Cas-regulated ATP depletion antiviral strategy.
原核生物已经进化出多种针对病毒感染的防御策略，包括通过CRISPR-Cas系统降解外源核酸以及通过耗尽核苷酸池来抑制DNA和RNA合成。在此，我们报告了一种III型CRISPR-Cas调节的三磷酸腺苷（ATP）消耗的抗病毒机制，即ATP在被cA或cA激活后，被CRISPR-Cas相关腺苷脱氨酶（CAAD）转化为三磷酸肌苷（ITP），随后被Nudix水解酶水解为一磷酸肌苷（IMP），最终导致细胞生长停滞。CAAD的无活性和激活形式的冷冻电子显微镜结构，以及生化证据，揭示了cA或cA如何与CRISPR相关的罗斯曼折叠（CARF）结构域结合并消除CAAD的自抑制作用，诱导显著的构象变化，重塑CAAD的结构并诱导其脱氨酶活性。我们的结果揭示了一种CRISPR-Cas调节的ATP消耗抗病毒策略的机制。
