Abstract：
Direct structural and dynamic characterization of protein conformers in solution is highly desirable but currently impractical. Herein, we developed a single molecule gold plasmonic nanopore system for observation of protein allostery, enabling us to monitor translocation dynamics and conformation transition of proteins by ion current detection and SERS spectrum measurement, respectively. Allosteric transition of calmodulin (CaM) was elaborately probed by the nanopore system. Two conformers of CaM were well-resolved at a single-molecule level using both the ion current blockage signal and the SERS spectra. The collected SERS spectra provided structural evidence to confirm the interaction between CaM and the gold plasmonic nanopore, which was responsible for the different translocation behaviors of the two conformers. SERS spectra revealed the amino acid residues involved in the conformational change of CaM upon calcium binding. The results demonstrated that the excellent spectral characterization furnishes a single-molecule nanopore technique with an advanced capability of direct structure analysis.
摘要：
溶液中蛋白质构象异构体的直接结构和动态表征是非常需要的，但目前是不切实际的。在这里，我们开发了一个单分子金等离子体纳米孔系统，用于观察蛋白质变构，使我们能够通过离子电流检测和SERS光谱测量来监测蛋白质的易位动力学和构象转换，分别。钙调蛋白（CaM）的变构转变被纳米孔系统精心探测。使用离子电流阻断信号和SERS光谱在单分子水平上很好地分辨了CaM的两个构象异构体。收集的SERS光谱提供了结构证据，以证实CaM和金等离子体纳米孔之间的相互作用，这是两个构象异构体不同的易位行为的原因。SERS光谱揭示了参与钙结合时CaM构象变化的氨基酸残基。结果表明，出色的光谱表征为单分子纳米孔技术提供了先进的直接结构分析能力。
