Institute for Surface and Interface Science, University of California Irvine, Irvine, CA 92697-2375, USA.
Science. 2012 Jan 20;335(6066):319-24. doi: 10.1126/science.1214824.
Tethering a single lysozyme molecule to a carbon nanotube field-effect transistor produced a stable, high-bandwidth transducer for protein motion. Electronic monitoring during 10-minute periods extended well beyond the limitations of fluorescence techniques to uncover dynamic disorder within a single molecule and establish lysozyme as a processive enzyme. On average, 100 chemical bonds are processively hydrolyzed, at 15-hertz rates, before lysozyme returns to its nonproductive, 330-hertz hinge motion. Statistical analysis differentiated single-step hinge closure from enzyme opening, which requires two steps. Seven independent time scales governing lysozyme's activity were observed. The pH dependence of lysozyme activity arises not from changes to its processive kinetics but rather from increasing time spent in either nonproductive rapid motions or an inactive, closed conformation.
将单个溶菌酶分子连接到碳纳米管场效应晶体管上，产生了一种用于蛋白质运动的稳定、高带宽传感器。在 10 分钟的时间内进行电子监测，远远超出了荧光技术的限制，揭示了单个分子内的动态无序，并将溶菌酶确定为一个连续酶。平均而言，在溶菌酶返回其非生产性的 330 赫兹铰链运动之前，100 个化学键以 15 赫兹的速率连续水解。统计分析将单步铰链关闭与需要两步的酶打开区分开来。观察到七个独立的时间尺度来控制溶菌酶的活性。溶菌酶活性的 pH 依赖性不是来自于其连续动力学的变化，而是来自于其在非生产性快速运动或非活性、关闭构象中花费的时间增加。
