Designing nanosensors based on charged derivatives of gramicidin A
Designing nanosensors based on charged derivatives of gramicidin A
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DOI：
10.1021/ja0711819
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发表时间：
2007-08-08
影响因子：
15
通讯作者：
Mayer, Michael
中科院分区：
文献类型：
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作者：
Capone, Ricardo;Blake, Steven;Mayer, Michael
在单分子尺度上检测化学过程是灵敏分析测定的最终目标。我们最近报道了通过监测短杆菌肽A（GA）衍生物与溶液中的分析物反应后的单离子通道电导的变化来检测单个分子上的化学修饰的可能性。这些基于肽的纳米传感器检测反应诱导的gA衍生物电荷变化，这些衍生物被设计为在其C末端附近携带特定官能团。(1)在这里，我们讨论了五个关键的设计参数，以优化这种化学调节离子通道传感器的性能。为了实现测量连接到gA孔的C-末端的基团的电荷变化的有效传感器，应当满足以下条件：（1）电荷变化应当尽可能靠近孔的入口发生;（2）反应前后的电荷应当在操作pH范围内明确限定;（3）记录缓冲液的离子强度应尽可能低，同时保持可检测的离子流通过孔;（4）施加的跨膜电压应尽可能高，同时保持稳定的膜;（5）支持膜中的脂质应该是两性离子的或与gA的衍生物带不同的电荷。结果表明，在高跨膜电位（> 100 mV）和低离子强度的记录缓冲液（
Detection of chemical processes on a single molecule scale is the ultimate goal of sensitive analytical assays. We recently reported the possibility to detect chemical modifications on individual molecules by monitoring a change in the single ion channel conductance of derivatives of gramicidin A (gA) upon reaction with analytes in solution. These peptide-based nanosensors detect reaction-induced changes in the charge of gA derivatives that were engineered to carry specific functional groups near their C-terminus.(1) Here, we discuss five key design parameters to optimize the performance of such chemomodulated ion channel sensors. In order to realize an effective sensor that measures changes in charge of groups attached to the C-terminus of a gA pore, the following conditions should be fulfilled: (1) the change in charge should occur as close to the entrance of the pore as possible; (2) the charge before and after reaction should be well-defined within the operational pH range; (3) the ionic strength of the recording buffer should be as low as possible while maintaining a detectable flow of ions through the pore; (4) the applied transmembrane voltage should be as high as possible while maintaining a stable membrane; (5) the lipids in the supporting membrane should either be zwitterionic or charged differently than the derivative of gA. We show that under the condition of high applied transmembrane potential (> 100 mV) and low ionic strength of the recording buffer (