Sequence-dependent gating of an ion channel by DNA hairpin molecules.
Sequence-dependent gating of an ion channel by DNA hairpin molecules.
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DOI：
10.1093/nar/gkl754
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发表时间：
2006
影响因子：
14.9
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中科院分区：
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当在单分子电泳条件下被α-溶血素纳米级孔捕获时，DNA发夹产生离子电流特征。当捕获时，由单个DNA发夹产生的门控模式可用于区分单个碱基对或甚至单个核苷酸的差异[Vercoutere，W.A.等人（2003）Nucleic Acids Res.，31，1311-1318]。在这里，我们调查的机制（S），可能占离子电流门控签名。由具有3-12 bp茎的DNA发夹分子产生的电导状态的离子电流电阻曲线在10和12 bp之间显示出电阻的平台，表明具有10-12 bp茎的发夹跨越孔前庭。具有9-12 bp茎的DNA发夹产生具有相同相对电导状态的门控签名。对一系列9-10 bp DNA发夹的电导态停留时间和表观活化能的系统比较表明，3′和5′末端在α-溶血素孔前庭内的极限孔径处或附近相互作用。提出的模型可能是有用的预测和解释DNA检测使用纳米孔检测器。此外，这个定义明确的分子系统可能被证明是有用的研究模型的配体门控通道的生物膜。
DNA hairpins produce ionic current signatures when captured by the alpha-hemolysin nano-scale pore under conditions of single molecule electrophoresis. Gating patterns produced by individual DNA hairpins when captured can be used to distinguish differences of a single base pair or even a single nucleotide [Vercoutere,W.A. et al. (2003) Nucleic Acids Res., 31, 1311–1318]. Here we investigate the mechanism(s) that may account for the ionic current gating signatures. The ionic current resistance profile of conductance states produced by DNA hairpin molecules with 3–12 bp stems showed a plateau in resistance between 10 and 12 bp, suggesting that hairpins with 10–12 bp stems span the pore vestibule. DNA hairpins with 9–12 bp stems produced gating signatures with the same relative conductance states. Systematic comparison of the conductance state dwell times and apparent activation energies for a series of 9–10 bp DNA hairpins suggest that the 3′ and 5′ ends interact at or near the limiting aperture within the vestibule of the alpha-hemolysin pore. The model presented may be useful in predicting and interpreting DNA detection using nanopore detectors. In addition, this well-defined molecular system may prove useful for investigating models of ligand-gated channels in biological membranes.