Pastoriza-Gallego Manuela, Thiébot Bénédicte, Bacri Laurent, Auvray Loïc, Pelta Juan
LAMBE UMR 8587, Université Cergy-Pontoise, Université Paris-Seine, 95302, Cergy-Pontoise, France.
LAMBE UMR 8587, Université Evry, CNRS, CEA, Université Paris-Saclay, 91025, Evry, France.
Eur Phys J E Soft Matter. 2018 May 11;41(5):58. doi: 10.1140/epje/i2018-11661-4.
We describe the behaviour of a polyelectrolyte in confined geometry. The transport of a polyelectrolyte, dextran sulfate, through a recombinant protein channel, aerolysin, inserted into a planar lipid bilayer is studied as a function of applied voltage and polyelectrolyte concentration and chain length. The aerolysin pore has a weak geometry asymmetry, a high number of charged residues and the polyelectrolyte is strongly negatively charged. The resulting current blockades were characterized by short and long dwelling times. Their frequency varies exponentially as a function of applied voltage and linearly as a function of polyelectrolyte concentration. The long blockade duration decreases exponentially when the electrical force increases. The ratio of the population of short events to the one of long events decreases when the applied voltage increases and displays an exponential variation. The long residence time increases with the polyelectrolyte chain length. We measure a reduction of the effective charge of the polyelectrolyte at the pore entry and inside the channel. For a fixed applied voltage, + / - 100 mV, at both sides of the protein pore entrance, the events frequency is similar as a function of dextran sulfate concentration. The mean blockade durations are independent of polyelectrolyte concentration and are similar for both entrances of the pore and remain constant as a function of the electrical force.
我们描述了聚电解质在受限几何结构中的行为。研究了聚电解质硫酸葡聚糖通过插入平面脂质双分子层的重组蛋白通道气溶素的传输，该传输是施加电压、聚电解质浓度和链长的函数。气溶素孔具有较弱的几何不对称性、大量带电残基，且聚电解质带强负电荷。所产生的电流阻断以短和长停留时间为特征。它们的频率随施加电压呈指数变化，随聚电解质浓度呈线性变化。当电力增加时，长阻断持续时间呈指数下降。当施加电压增加时，短事件群体与长事件群体的比例下降，并呈现指数变化。长停留时间随聚电解质链长增加。我们测量了聚电解质在孔入口处和通道内有效电荷的减少。对于固定的施加电压，即蛋白孔入口两侧的±100 mV，事件频率作为硫酸葡聚糖浓度的函数是相似的。平均阻断持续时间与聚电解质浓度无关，对于孔的两个入口是相似的，并且作为电力的函数保持恒定。
