A high ATP concentration enhances the cooperative translocation of the SARS coronavirus helicase nsP13 in the unwinding of duplex RNA
A high ATP concentration enhances the cooperative translocation of the SARS coronavirus helicase nsP13 in the unwinding of duplex RNA
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DOI：
10.1038/s41598-020-61432-1
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发表时间：
2020-03-11
影响因子：
4.6
通讯作者：
Kim, Dong-Eun
中科院分区：
文献类型：
--
作者：
Jang, Kyoung-Jin;Jeong, Seonghwan;Kim, Dong-Eun
严重急性呼吸综合征冠状病毒非结构蛋白13（severe acute respiratory syndrome coronavirus nonstructural protein 13，SCV nsP 13）是一种超家族1解旋酶，通过将双链RNA和DNA从5 '端向3 '端解旋，在病毒RNA复制过程中发挥重要作用。尽管nsP 13在病毒RNA复制中起假定的作用，但它容易通过合作易位解开双链体DNA。在此，nsP 13在双链体RNA解旋中表现出与双链体DNA不同的特征。nsP 13对双链RNA的持续合成能力比对双链DNA的持续合成能力差。更重要的是，nsP 13通过增加5 ' -ss尾部长度而无效地解旋双链体RNA。随着nsP 13浓度的增加，解螺旋DNA的量增加，解螺旋RNA的量减少。双链RNA/nsP 13复合物的积累随着nsP 13浓度的增加而增加。双链体RNA解旋中ATP浓度的增加缓解了双链体RNA解旋的减少。因此，nsP 13对作为解旋反应底物的双链体RNA具有强亲和力，这需要增加的ATP来促进解旋双链体RNA。我们的研究结果表明，双链RNA是一个优选的底物的解旋酶活性的nsP 13比双链DNA在高ATP浓度。
Severe acute respiratory syndrome coronavirus nonstructural protein 13 (SCV nsP13), a superfamily 1 helicase, plays a central role in viral RNA replication through the unwinding of duplex RNA and DNA with a 5 ' single-stranded tail in a 5 ' to 3 ' direction. Despite its putative role in viral RNA replication, nsP13 readily unwinds duplex DNA by cooperative translocation. Herein, nsP13 exhibited different characteristics in duplex RNA unwinding than that in duplex DNA. nsP13 showed very poor processivity on duplex RNA compared with that on duplex DNA. More importantly, nsP13 inefficiently unwinds duplex RNA by increasing the 5 ' -ss tail length. As the concentration of nsP13 increased, the amount of unwound duplex DNA increased and that of unwound duplex RNA decreased. The accumulation of duplex RNA/nsP13 complexes increased as the concentration of nsP13 increased. An increased ATP concentration in the unwinding of duplex RNA relieved the decrease in duplex RNA unwinding. Thus, nsP13 has a strong affinity for duplex RNA as a substrate for the unwinding reaction, which requires increased ATPs to processively unwind duplex RNA. Our results suggest that duplex RNA is a preferred substrate for the helicase activity of nsP13 than duplex DNA at high ATP concentrations.