Department of Molecular Biology & Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada.
J Am Chem Soc. 2010 Mar 3;132(8):2663-71. doi: 10.1021/ja908508j.
Double-helical DNA has been shown to conduct both electrons and electron holes, the latter over distances of >20 nm. DNA is thus a material of significant interest for the bottom-up construction of nanocircuitry. Here, we describe a contractile DNA nanoswitch, which can toggle between a structurally extended "off" state and a contracted "on" state, with a 40-fold conductivity difference between the two. To turn on, two short motifs of guanine-guanine mismatches in an otherwise standard double helix synapse to form a conductive G-quadruplex, bypassing an insulating element within the helix. This switch can be turned repeatedly on by treatment with millimolar concentrations of K(+) and turned off by sequestration of the K(+) by a crown ether. Circular dichroism and thymine-thymine photocross-linking experiments reveal that strand orientations within the on state G-quadruplex are wholly antiparallel and that the two conductive double-helices interface with the same face of the quadruplex. Although this DNA nanoswitch is chemically gated, it should be adaptable to other kinds of gating and thus serve as a prototype for increasingly sophisticated and complex electronic devices made of DNA.
双链 DNA 已被证明可以同时传导电子和空穴，后者的距离超过 20nm。因此，DNA 是自下而上构建纳米电路的重要材料。在这里，我们描述了一种可伸缩的 DNA 纳米开关，它可以在结构伸展的“关闭”状态和收缩的“开启”状态之间切换，两种状态之间的电导率差异高达 40 倍。为了开启，两条短的鸟嘌呤-鸟嘌呤错配序列在标准双链螺旋的突触处形成一个导电的 G-四链体，绕过螺旋内的一个绝缘元件。这个开关可以通过用毫摩尔浓度的 K(+)处理来反复开启，并通过冠醚捕获 K(+)来关闭。圆二色性和胸腺嘧啶-胸腺嘧啶光交联实验表明，在开启状态下 G-四链体中的链取向完全是反平行的，并且两个导电的双链与四链体的同一面相互作用。尽管这种 DNA 纳米开关是化学门控的，但它应该可以适应其他类型的门控，因此可以作为越来越复杂和复杂的 DNA 电子设备的原型。
