Department of Physics and Astronomy, University of California, Irvine, California 92697, USA.
Nano Lett. 2013 Feb 13;13(2):625-31. doi: 10.1021/nl304209p. Epub 2013 Jan 24.
Single-molecule experimental methods have provided new insights into biomolecular function, dynamic disorder, and transient states that are all invisible to conventional measurements. A novel, nonfluorescent single-molecule technique involves attaching single molecules to single-walled carbon nanotube field-effective transistors (SWNT FETs). These ultrasensitive electronic devices provide long-duration, label-free monitoring of biomolecules and their dynamic motions. However, generalization of the SWNT FET technique first requires design rules that can predict the success and applicability of these devices. Here, we report on the transduction mechanism linking enzymatic processivity to electrical signal generation by a SWNT FET. The interaction between SWNT FETs and the enzyme lysozyme was systematically dissected using eight different lysozyme variants synthesized by protein engineering. The data prove that effective signal generation can be accomplished using a single charged amino acid, when appropriately located, providing a foundation to widely apply SWNT FET sensitivity to other biomolecular systems.
单分子实验方法为生物分子功能、动态无序和瞬态状态提供了新的见解，这些都是传统测量方法无法观察到的。一种新颖的非荧光单分子技术涉及将单分子附着到单壁碳纳米管场效应晶体管 (SWNT FET) 上。这些超灵敏的电子设备可长时间、无标记地监测生物分子及其动态运动。然而，SWNT FET 技术的推广首先需要设计规则，这些规则可以预测这些器件的成功和适用性。在这里，我们报告了将酶的连续性与 SWNT FET 产生的电信号联系起来的转导机制。通过使用蛋白质工程合成的 8 种不同的溶菌酶变体，系统地剖析了 SWNT FET 与酶溶菌酶之间的相互作用。这些数据证明，当适当定位时，单个带电氨基酸可以实现有效的信号产生，为将 SWNT FET 的灵敏度广泛应用于其他生物分子系统提供了基础。
