Coupling into the base pair stack is necessary for DNA-Mediated Electrochemistry
Coupling into the base pair stack is necessary for DNA-Mediated Electrochemistry
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DOI：
10.1021/bc0700483
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发表时间：
2007-09-01
影响因子：
4.7
通讯作者：
Barton, Jacqueline K.
中科院分区：
文献类型：
--
作者：
Gorodetsky, Alon A.;Green, Omar;Barton, Jacqueline K.
研究了不同氧化还原探针修饰的DNA膜的电化学性质。实验的特点是两个氧化还原探针结合到DNA的两个表面上：蒽醌（AQ）修饰的尿苷纳入巯基化的DNA在金（Au）和2，2，6，6-四甲基哌啶I-氧基（克里思）修饰的尿苷芘标记的DNA在高取向热解石墨（HOPG）。这些标签的电化学时，纳入DNA已检查在DNA膜含有良好匹配和不匹配的DNA。DNA介导的电化学被发现是有效的克里思探针连接乙炔接头，但不饱和克里思连接通过乙二胺接头。对于AQ探针，发现DNA介导的电化学具有与尿苷的乙炔接头，但不具有与寡核苷酸的5'末端的烷基链。通过乙炔键连接的探针实现了大的电化学信号和干预碱基错配的有效辨别，而通过饱和键连接的探针表现出仅与直接表面到探针电荷转移和差的错配辨别相关的小的电化学信号。因此，DNA电化学与这些探针的显着影响的化学性质，它们的连接到DNA。这些结果强调了有效耦合到pi堆栈对于远程DNA介导的电化学的重要性。
The electrochemistry of DNA films modified with different redox probes linked to DNA through saturated and conjugated tethers was investigated. Experiments feature two redox probes bound to DNA on two surfaces: anthraquinone (AQ)-modified uridines incorporated into thiolated DNA on gold (Au) and 2,2,6,6-tetramethylpiperidine I-oxyl (TEMPO)-modified uridines in pyrene-labeled DNA on highly oriented pyrolytic graphite (HOPG). The electrochemistry of these labels when incorporated into DNA has been examined in DNA films containing both well matched and mismatched DNA. DNA-mediated electrochemistry is found to be effective for the TEMPO probe linked with an acetylene linker but not for a saturated TEMPO connected through an ethylenediamine linker. For the AQ probe, DNA-mediated electrochemistry is found with an acetylene linker to uridine but not with an alkyl chain to the 5' terminus of the oligonucleotide. Large electrochemical signals and effective discrimination of intervening base mismatches are achieved for the probes connected through the acetylene linkages, while probes connected through saturated linkages exhibit small electrochemical signals associated only with direct surface to probe charge transfer and poor mismatch discrimination. Thus DNA electrochemistry with these probes is dramatically influenced by the chemical nature of their linkage to DNA. These results highlight the importance of effective coupling into the pi-stack for long-range DNA-mediated electrochemistry.