Inorganic Chemistry I, Bioinorganic Chemistry, Faculty of Chemistry and Biochemistry, Ruhr-University Bochum, Universitätsstrasse 150, 44801 Bochum, Germany.
Chemphyschem. 2012 Jan 16;13(1):131-9. doi: 10.1002/cphc.201100578. Epub 2011 Sep 20.
Gold-surface grafted peptide nucleic acid (PNA) strands, which carry a redox-active ferrocene tag, present unique tools to electrochemically investigate their mechanical bending elasticity based on the kinetics of electron-transfer (ET) processes. A comparative study of the mechanical bending properties and the thermodynamic stability of a series of 12-mer Fc-PNA⋅DNA duplexes was carried out. A single basepair mismatch was integrated at all possible strand positions to provide nanoscopic insights into the physicochemical changes provoked by the presence of a single basepair mismatch with regard to its position within the strand. The ET processes at single mismatch Fc-PNA⋅DNA modified surfaces were found to proceed with increasing diffusion limitation and decreasing standard ET rate constants k(0) when the single basepair mismatch was dislocated along the strand towards its free-dangling Fc-modified end. The observed ET characteristics are considered to be due to a punctual increase in the strand elasticity at the mismatch position. The kinetic mismatch discrimination with respect to the fully-complementary duplex presents a basis for an electrochemical DNA sensing strategy based on the Fc-PNA⋅DNA bending dynamics for loosely packed monolayers. In a general sense, the strand elasticity presents a further physicochemical property which is affected by a single basepair mismatch which may possibly be used as a basis for future DNA sensing concepts for the specific detection of single basepair mismatches.
金表面接枝肽核酸（PNA）链，携带氧化还原活性的二茂铁标记，为电化学研究其机械弯曲弹性提供了独特的工具，基于电子转移（ET）过程的动力学。对一系列 12 聚体 Fc-PNA⋅DNA 双链体的机械弯曲性能和热力学稳定性进行了比较研究。在所有可能的链位置都集成了一个单碱基对错配，以提供纳米级的见解，了解在链内位置存在单个碱基对错配时引起的物理化学变化。在单碱基对错配 Fc-PNA⋅DNA 修饰表面上的 ET 过程被发现随着扩散限制的增加和标准 ET 速率常数 k(0)的降低而进行，当单碱基对错配沿着链向其游离悬垂的 Fc 修饰端位移时。观察到的 ET 特征被认为是由于在错配位置处链弹性的突然增加。与完全互补双链体的动力学错配区分提供了基于 Fc-PNA⋅DNA 弯曲动力学的电化学 DNA 传感策略的基础，用于松散堆积的单层。一般来说，链弹性是受单个碱基对错配影响的另一个物理化学性质，它可能被用作未来特定检测单个碱基对错配的 DNA 传感概念的基础。
