Interfering with nucleotide excision by the coronavirus 3'-to-5' exoribonuclease.
Interfering with nucleotide excision by the coronavirus 3'-to-5' exoribonuclease.
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干扰冠状病毒 3 至 5 核糖核酸外切酶的核苷酸切除。
DOI：
10.1101/2022.08.11.503614
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Arnold,JamieJ
中科院分区：
文献类型：
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作者：
Chinthapatla,Rukesh;Sotoudegan,Mohamad;Anderson,Thomas;Moustafa,IbrahimM;Passow,KellanT;Kennelly,SamanthaA;Moorthy,Ramkumar;Dulin,David;Feng,JoyY;Harki,DanielA;Kirchdoerfer,Robert;Cameron,CraigE;Arnold,JamieJ
一些最有效的抗病毒治疗剂是核糖核苷（酸）类似物。冠状病毒中3′至5′校对核糖核酸外切酶（ExoN）的存在降低了许多核糖核苷酸类似物的效力。干扰ExoN活性的能力将为控制SARS-CoV-2感染创造新的可能性。ExoN由nsp 14和nsp 10蛋白的1：1复合物形成。我们已经使用一个强大的，定量系统，揭示了特异性和水解效率的决定因素，纯化和表征ExoN。双链RNA优于单链RNA。核苷酸切除是分布性的，在单个结合事件中仅水解一个或两个核苷酸。末端碱基对的组成调节切除。一个停滞的SARS-CoV-2复制酶与正确或不正确终止的产物复合，阻止了切除，这表明错配的末端不足以取代复制酶。最后，我们发现了3′-RNA末端的几种修饰，这些修饰干扰或阻断了ExoN催化的切除。虽然3′-OH促进了具有正常核糖构型的核苷酸的水解，但对于具有平面核糖构型的核苷酸（例如存在于由蝰蛇蛋白产生的抗病毒核苷酸中的核苷酸），不需要该取代基。抗ExoN的抗病毒核糖核苷酸的设计应该是可行的。
Some of the most efficacious antiviral therapeutics are ribonucleos(t)ide analogs. The presence of a 3′-to-5′ proofreading exoribonuclease (ExoN) in coronaviruses diminishes the potency of many ribonucleotide analogs. The ability to interfere with ExoN activity will create new possibilities for control of SARS-CoV-2 infection. ExoN is formed by a 1:1 complex of nsp14 and nsp10 proteins. We have purified and characterized ExoN using a robust, quantitative system that reveals determinants of specificity and efficiency of hydrolysis. Double-stranded RNA is preferred over single-stranded RNA. Nucleotide excision is distributive, with only one or two nucleotides hydrolyzed in a single binding event. The composition of the terminal basepair modulates excision. A stalled SARS-CoV-2 replicase in complex with either correctly or incorrectly terminated products prevents excision, suggesting that a mispaired end is insufficient to displace the replicase. Finally, we have discovered several modifications to the 3′-RNA terminus that interfere with or block ExoN-catalyzed excision. While a 3′-OH facilitates hydrolysis of a nucleotide with a normal ribose configuration, this substituent is not required for a nucleotide with a planar ribose configuration such as that present in the antiviral nucleotide produced by viperin. Design of ExoN-resistant, antiviral ribonucleotides should be feasible.