Faculty of Physics and Center for NanoScience (CeNS), Ludwig-Maximilians-University, Munich, Germany; Department of Cancer Biology, Dana-Farber Cancer Institute and Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts; Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, Massachusetts.
Department of Cancer Biology, Dana-Farber Cancer Institute and Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts; Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, Massachusetts.
Biophys J. 2022 Dec 20;121(24):4860-4866. doi: 10.1016/j.bpj.2022.08.040. Epub 2022 Aug 31.
Nanoscale stepper motors such as kinesin and dynein play a key role in numerous natural processes such as mitotic spindle formation during cell division or intracellular organelle transport. Their high efficacy in terms of operational speed and processivity has inspired the investigation of biomimetic technologies based on the use of programmable molecules. In particular, several designs of molecular walkers have been explored using DNA nanotechnology. Here, we study the actuation of a DNA-origami walker on a DNA-origami track based on three principles: 1) octapedal instead of bipedal walking for greater redundancy; 2) three pairs of orthogonal sequences, each of which fuels one repeatable stepping phase for cyclically driven motion with controlled directionality based on strain-based step selection; 3) designed size of only 3.5 nm per step on an origami track. All three principles are innovative in the sense that earlier demonstrations of steppers relied on a maximum of four legs on at least four orthogonal sequences to drive cyclic stepping, and took steps much larger than 3.4 nm in size. Using gel electrophoresis and negative-stain electron microscopy, we demonstrate cyclic actuation of DNA-origami structures through states defined by three sets of specific sequences of anchor points. However, this mechanism was not able to provide the intended control over directionality of movement. DNA-origami-based stepper motors will offer a future platform for investigating how increasing numbers of legs can be exploited to achieve robust stepping with relatively small step sizes.
纳米级步进电机，如肌球蛋白和动力蛋白，在许多自然过程中发挥着关键作用，如细胞分裂过程中的有丝分裂纺锤体形成或细胞内细胞器运输。它们在操作速度和进程方面的高效率激发了对基于使用可编程分子的仿生技术的研究。特别是，已经使用 DNA 纳米技术探索了几种分子步行者的设计。在这里，我们研究了基于三个原理的 DNA 折纸步行者在 DNA 折纸轨道上的驱动：1）八足而不是双足行走以提高冗余度；2）三对正交序列，每对序列为周期性驱动运动提供一个可重复的步进相，方向可控，基于基于应变的步选择；3）在折纸轨道上的设计尺寸仅为每个步 3.5nm。所有三个原理都是创新的，因为早期的步进器演示依赖于至少四个正交序列上最多四个腿来驱动循环步进，并且步长比 3.4nm 大得多。使用凝胶电泳和负染色电子显微镜，我们通过三组特定的锚点序列证明了 DNA 折纸结构的循环驱动。然而，这种机制无法提供对运动方向的预期控制。基于 DNA 折纸的步进电机将为研究如何利用更多的腿来实现相对较小步长的稳健步进提供一个未来的平台。
