Viral packaging ATPases utilize a glutamate switch to couple ATPase activity and DNA translocation
Viral packaging ATPases utilize a glutamate switch to couple ATPase activity and DNA translocation
复制标题
病毒包装 ATP 酶利用谷氨酸开关来耦合 ATP 酶活性和 DNA 易位
DOI：
10.1073/pnas.2024928118
复制
发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Arya, Gaurav
中科院分区：
文献类型：
--
作者：
Pajak, Joshua;Atz, Rockney;Hilbert, Brendan J.;Morais, Marc C.;Kelch, Brian A.;Jardine, Paul J.;Arya, Gaurav
许多病毒在复制过程中利用环状包装ATP酶将双链DNA转运到原壳体中。这种ATP酶的机械化学循环中的关键步骤是ATP结合，其导致马达内的亚基紧紧地抓住DNA。在这里，我们探测ATP结合耦合到DNA夹持的潜在分子机制，并表明在AAA+酶中发现的谷氨酸开关残基是病毒包装ATP酶中这种耦合的核心。使用通过分子动力学模拟计算的自由能景观，我们确定了ATP和ADP结合状态下ATP酶活性位点的稳定构象状态。我们的研究结果表明，催化谷氨酸残基转换从一个活跃的到一个不活跃的姿势ATP水解后，并指定为谷氨酸开关的残基是必要的调节这种过渡。此外，我们通过互信息分析确定了由谷氨酸开关介导的分子内信号传导途径，该谷氨酸开关负责将ATP结合耦合到DNA夹持基序的构象转变。我们证实了这些预测与结构和功能的实验测量。具体地说，我们表明ADP结合的P74-26包装ATP酶的晶体结构与模拟预测的结构偶联一致，我们进一步表明，破坏预测的信号传导途径确实会使ATP酶活性与φ29 DNA包装马达中的DNA易位活性相分离。因此，我们的工作建立了一个信号通路，耦合病毒DNA包装马达的化学和机械事件。
Many viruses utilize ringed packaging ATPases to translocate double-stranded DNA into procapsids during replication. A critical step in the mechanochemical cycle of such ATPases is ATP binding, which causes a subunit within the motor to grip DNA tightly. Here, we probe the underlying molecular mechanism by which ATP binding is coupled to DNA gripping and show that a glutamate-switch residue found in AAA+ enzymes is central to this coupling in viral packaging ATPases. Using free-energy landscapes computed through molecular dynamics simulations, we determined the stable conformational state of the ATPase active site in ATP- and ADP-bound states. Our results show that the catalytic glutamate residue transitions from an active to an inactive pose upon ATP hydrolysis and that a residue assigned as the glutamate switch is necessary for regulating this transition. Furthermore, we identified via mutual information analyses the intramolecular signaling pathway mediated by the glutamate switch that is responsible for coupling ATP binding to conformational transitions of DNA-gripping motifs. We corroborated these predictions with both structural and functional experimental measurements. Specifically, we showed that the crystal structure of the ADP-bound P74-26 packaging ATPase is consistent with the structural coupling predicted from simulations, and we further showed that disrupting the predicted signaling pathway indeed decouples ATPase activity from DNA translocation activity in the φ29 DNA packaging motor. Our work thus establishes a signaling pathway that couples chemical and mechanical events in viral DNA packaging motors.
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DOI：
--
发表时间：
2020
期刊：
bioRxiv
影响因子：
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