Manganese-dependent polioviruses caused by mutations within the viral polymerase
Manganese-dependent polioviruses caused by mutations within the viral polymerase
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DOI：
10.1128/jvi.77.9.5378-5388.2003
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发表时间：
2003-05-01
影响因子：
5.4
通讯作者：
Andino, R
中科院分区：
文献类型：
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作者：
Crotty, S;Gohara, D;Andino, R
病毒RNA依赖性RNA聚合酶表现出很大的序列多样性。在真核生物的正链RNA病毒的所有聚合酶中，只有六个核心氨基酸是保守的。在探索这些完全保守的残基之一，天冬酰胺297在原型脊髓灰质炎病毒聚合酶3D（pol）的功能，我们确定了三个可行的突变体与非经典氨基酸在这个保守的位置。虽然天冬酰胺297可以取代甘氨酸或丙氨酸在这些突变体中，病毒表现出Mn 2+依赖的RNA复制和病毒生长。所有已知的细菌、真核生物和病毒生物的RNA聚合酶和复制型聚合酶被认为在体内是镁依赖性的，因此这些突变型脊髓灰质炎病毒可能代表了第一批需要替代聚合酶阳离子的病毒。这些结果证明了病毒RNA依赖性RNA聚合酶的极端功能灵活性。此外，聚合酶的核苷酸结合口袋中严格保守的残基可以以支持病毒产生的方式改变的发现表明，靶向该酶区域的药物仍然容易受到耐药逃逸突变体的问题的影响。
Viral RNA-dependent RNA polymerases exhibit great sequence diversity. Only six core amino acids are conserved across all polymerases of positive-strand RNA viruses of eukaryotes. While exploring the function of one of these completely conserved residues, asparagine 297 in the prototypic poliovirus polymerase 3D(pol), we identified three viable mutants with noncanonical amino acids at this conserved position. Although asparagine 297 could be replaced by glycine or alanine in these mutants, the viruses exhibited Mn2+-dependent RNA replication and viral growth. All known RNA polymerases and replicative polymerases of bacterial, eukaryotic, and viral organisms are thought to be magnesium dependent in vivo, and therefore these mutant polioviruses may represent the first viruses with a requirement for an alternative polymerase cation. These results demonstrate the extreme functional flexibility of viral RNA-dependent RNA polymerases. Furthermore, the finding that strictly conserved residues in the nucleotide binding pocket of the polymerase can be altered in a manner that supports virus production suggests that drugs targeting this region of the enzyme will still be susceptible to the problem of drug-resistant escape mutants.