High-Resolution Size-Discrimination of Single Nonionic Synthetic Polymers with a Highly Charged Biological Nanopore

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• 作者：Gerhard Baaken ; Ibrahim Halimeh ; Laurent Bacri ; Juan Pelta ; Abdelghani Oukhaled ; Jan C. Behrends
• 刊名：ACS Nano
• 出版年：2015
• 出版时间：June 23, 2015
• 年：2015
• 卷：9
• 期：6
• 页码：6443-6449
• 全文大小：483K
• ISSN：1936-086X

文摘

Electrophysiological studies of the interaction of polymers with pores formed by bacterial toxins (1) provide a window on single molecule interaction with proteins in real time, (2) report on the behavior of macromolecules in confinement, and (3) enable label-free single molecule sensing. Using pores formed by the staphylococcal toxin 伪-hemolysin (aHL), a particularly pertinent observation was that, under high salt conditions (3鈥? M KCl), the current through the pore is blocked for periods of hundreds of microseconds to milliseconds by poly(ethylene glycol) (PEG) oligomers (degree of polymerization approximately 10鈥?0). Notably, this block showed monomeric sensitivity on the degree of polymerization of individual oligomers, allowing the construction of size or mass spectra from the residual current values. Here, we show that the current through the pore formed by aerolysin (AeL) from Aeromonas hydrophila is also blocked by PEG but with drastic differences in the voltage-dependence of the interaction. In contrast to aHL, AeL strongly binds PEG at high transmembrane voltages. This fact, which is likely related to AeL鈥檚 highly charged pore wall, allows discrimination of polymer sizes with particularly high resolution. Multiple applications are now conceivable with this pore to screen various nonionic or charged polymers.