Molecular Scale Conductance Photoswitching in Engineered Bacteriorhodopsin
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- 作者：Olivia Berthoumieu ; Amol V. Patil ; Wang Xi ; Lubica Aslimovska ; Jason J. Davis ; Anthony Watts
- 刊名：Nano Letters
- 出版年：2012
- 出版时间：February 8, 2012
- 年：2012
- 卷：12
- 期：2
- 页码：899-903
- 全文大小：257K
- 年卷期：v.12,no.2(February 8, 2012)
- ISSN：1530-6992
文摘
Bacteriorhodopsin (BR) is a robust light-driven proton pump embedded in the purple membrane of the extremophilic archae Halobacterium salinarium. Its photoactivity remains in the dry state, making BR of significant interest for nanotechnological use. Here, in a novel configuration, BR was depleted from most of its endogenous lipids and covalently and asymmetrically anchored onto a gold electrode through a strategically located and highly responsive cysteine mutation; BR has no indigenous cysteines. Chemisorption on gold was characterized by surface plasmon resonance, reductive striping voltammetry, ellipsometry, and atomic force microscopy (AFM). For the first time, the conductance of isolated protein trimers, intimately probed by conducting AFM, was reproducibly and reversibly switched under wavelength-specific conditions (mean resistance of 39 卤 12 M惟 under illumination, 137 卤 18 M惟 in the dark), demonstrating a surface stability that is relevant to potential nanodevice applications.