Mereuta Loredana, Roy Mahua, Asandei Alina, Lee Jong Kook, Park Yoonkyung, Andricioaei Ioan, Luchian Tudor
1] Department of Physics, Alexandru I. Cuza University, Iasi, Romania [2].
1] Department of Chemistry, University of California, Irvine CA 92697, USA [2].
Sci Rep. 2014 Jan 27;4:3885. doi: 10.1038/srep03885.
The microscopic details of how peptides translocate one at a time through nanopores are crucial determinants for transport through membrane pores and important in developing nano-technologies. To date, the translocation process has been too fast relative to the resolution of the single molecule techniques that sought to detect its milestones. Using pH-tuned single-molecule electrophysiology and molecular dynamics simulations, we demonstrate how peptide passage through the α-hemolysin protein can be sufficiently slowed down to observe intermediate single-peptide sub-states associated to distinct structural milestones along the pore, and how to control residence time, direction and the sequence of spatio-temporal state-to-state dynamics of a single peptide. Molecular dynamics simulations of peptide translocation reveal the time- dependent ordering of intermediate structures of the translocating peptide inside the pore at atomic resolution. Calculations of the expected current ratios of the different pore-blocking microstates and their time sequencing are in accord with the recorded current traces.
肽如何一次一个地通过纳米孔的微观细节是决定其通过膜孔运输的关键因素，并且在纳米技术的发展中具有重要意义。迄今为止，相对于试图检测其各个阶段的单分子技术的分辨率而言，转运过程太快了。利用pH调节的单分子电生理学和分子动力学模拟，我们展示了肽通过α-溶血素蛋白的过程如何能够充分减慢，以观察与沿孔的不同结构阶段相关的中间单肽亚状态，以及如何控制单个肽的停留时间、方向和时空状态到状态动力学的顺序。肽转运的分子动力学模拟以原子分辨率揭示了孔内转运肽中间结构的时间依赖性排序。不同孔阻塞微状态的预期电流比率及其时间顺序的计算与记录的电流迹线一致。
