Helicases are essential for nearly all nucleic acid processes across the tree of life. Using Nanopore Tweezers we observed the small, fast steps taken by single RecQ helicases as they step along and unwind DNA at ultrahigh spatiotemporal resolution. By directly measuring conformational substates of RecQ we determine the coupling between helicase domain motions and chemical reactions that together produce forward motion along the DNA. Application of assisting and opposing forces shows that RecQ has a highly asymmetric energy landscape that reduces its sensitivity to opposing mechanical forces that could be encountered in vivo by molecular roadblocks such as DNA bound proteins. This energy landscape enables RecQ to maintain speed against an opposing load.

中文翻译：

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纳米孔镊子对 RecQ 构象变化的测量揭示了解旋酶运动的能量景观

解旋酶对于生命之树中几乎所有的核酸过程都是必不可少的。使用纳米孔镊子，我们观察到单个 RecQ 解旋酶在以超高时空分辨率步进和解开 DNA 时所采取的小而快速的步骤。通过直接测量 RecQ 的构象亚状态，我们确定解旋酶域运动和化学反应之间的耦合，这些化学反应共同产生沿 DNA 的向前运动。辅助力和反向力的应用表明 RecQ 具有高度不对称的能量景观，这降低了其对反向机械力的敏感性，这些反向机械力可能在体内通过分子障碍（如 DNA 结合蛋白）遇到。这种能量景观使 RecQ 能够在对抗相反负载的情况下保持速度。