Kovacic Suzana, Samii Laleh, Curmi Paul M G, Linke Heiner, Zuckermann Martin J, Forde Nancy R
IEEE Trans Nanobioscience. 2015 Apr;14(3):305-12. doi: 10.1109/TNB.2015.2393872. Epub 2015 Mar 2.
Molecular motors of the cell are protein-based, nanoscale machines, which use a variety of strategies to transduce chemical energy into mechanical work in the presence of a large thermal background. The design and construction of artificial molecular motors is one approach to better understand their basic physical principles. Here, we propose the concept of a protein-based, burnt-bridges ratchet, inspired by biological examples. Our concept, the lawnmower, utilizes protease blades to cleave peptide substrates, and uses the asymmetric substrate-product interface arising from productive cleavage to bias subsequent diffusion on the track (lawn). Following experimental screening to select a protease to act as the motor's blades, we chemically couple trypsin to quantum dots and demonstrate activity of the resulting lawnmower construct in solution. Accompanying Brownian dynamics simulations illustrate the importance for processivity of correct protease density on the quantum dot and spacing of substrates on the track. These results lay the groundwork for future tests of the protein-based lawnmower's motor performance characteristics.
细胞的分子马达是基于蛋白质的纳米级机器，在存在大量热背景的情况下，它们利用多种策略将化学能转化为机械功。人工分子马达的设计与构建是更好地理解其基本物理原理的一种方法。在此，我们受生物学实例启发，提出了基于蛋白质的“燃烧桥梁”棘轮的概念。我们的概念——“割草机”，利用蛋白酶刀片切割肽底物，并利用有效切割产生的不对称底物 - 产物界面来使后续在轨道（草坪）上的扩散产生偏差。在经过实验筛选以选择一种蛋白酶作为马达的刀片后，我们将胰蛋白酶化学偶联到量子点上，并证明了所得“割草机”构建体在溶液中的活性。伴随的布朗动力学模拟说明了量子点上正确的蛋白酶密度以及轨道上底物间距对持续性的重要性。这些结果为未来测试基于蛋白质的“割草机”的马达性能特征奠定了基础。
