Department of Chemistry, School of Environment, Beijing Normal University, Beijing, 100875, China.
Anal Chem. 2010 Feb 1;82(3):1166-9. doi: 10.1021/ac902813y.
The interaction of the metal ions Mg(2+), Zn(2+), Ni(2+), and Co(2+) with DNA-peptide nucleic acid (PNA) films on a gold surface is studied by electrochemical impedance spectroscopy in the presence of Fe(CN)(6) as the redox probe. Impedance data were analyzed with the help of a modified Randles' equivalent circuit. Changes in the charge-transfer resistance, R(CT), decreases in the order of Ni(2+) > Co(2+) > Zn(2+) > Mg(2+). We interpret these results in terms of stronger interactions for Ni(2+) with the DNA-PNA film compared to the other metal ions, potentially involving interactions with the nucleobases, presumably with the N7 of purines or the N3 of pyrimidines. On the basis of these observations, Ni(2+) was chosen to probe the detection of a C-T mismatch in 15-mer PNA-DNA films. Using Ni(2+), it is possible to detect a single C-T mismatch. The resulting DeltaR(CT) is larger for the PNA-DNA hybrid compared to that for the identical 15-mer DNA-DNA hybrid.
通过电化学阻抗谱研究了在[Fe(CN)(6)]（3-/4-）作为氧化还原探针的情况下，金属离子 Mg(2+)、Zn(2+)、Ni(2+)和 Co(2+)与金表面上的 DNA-肽核酸（PNA）膜的相互作用。通过修改后的兰德尔等效电路对阻抗数据进行了分析。荷转移电阻 R(CT)的变化顺序为 Ni(2+) > Co(2+) > Zn(2+) > Mg(2+)。我们根据这些结果解释说，与其他金属离子相比，Ni(2+)与 DNA-PNA 膜的相互作用更强，可能涉及与碱基的相互作用，可能涉及嘌呤的 N7 或嘧啶的 N3。基于这些观察结果，选择 Ni(2+)来探测 15 聚体 PNA-DNA 膜中的 C-T 错配。使用 Ni(2+)，可以检测到单个 C-T 错配。与相同的 15 聚体 DNA-DNA 杂交物相比，PNA-DNA 杂交物的 DeltaR(CT)更大。
