nsp12 transfers guanylyl onto SARS-CoV-2 plus strand subgenomic RNAs

Capping of viral mRNA starts with the transfer of a guanylyl residue onto the RNA`s phosphate moiety, creating the cap core structure (GpppA, also cap(-1)). SARS-CoV-2 Nsp12 has been shown to have this guanylyltransferase (GTase) activity, carrying out the addition of a GTP nucleotide to the 5' end of viral RNA, which can be inhibited by remdesivir triphosphate, the active form of the antiviral drug remdesivir (Yan et al, 2021; Walker et al, 2021).

病毒mRNA的帽状结构形成始于将鸟苷酸残基转移至RNA的磷酸基团，从而构建起帽状核心结构（GpppA，亦称为cap(-1)）。SARS-CoV-2的Nsp12已被证实具备此类鸟苷酸转移酶（GTase）活性，负责将鸟苷三磷酸核苷添加至病毒RNA的5'端，其过程可被抗病毒药物瑞德西韦的三磷酸形式所抑制（Yan等，2021年；Walker等，2021年）。