Kratochvílová Irena, Král Karel, Buncek Martin, Vísková Alena, Nespůrek Stanislav, Kochalska Anna, Todorciuc Tatiana, Weiter Martin, Schneider Bohdan
Institute of Physics, ASCR, v.v.i., Na Slovance 2, CZ-18221 Prague, Czech Republic.
Biophys Chem. 2008 Nov;138(1-2):3-10. doi: 10.1016/j.bpc.2008.08.005. Epub 2008 Aug 28.
The conductivity of DNA covalently bonded to a gold surface was studied by means of the STM technique. Various single- and double-stranded 32-nucleotide-long DNA sequences were measured under ambient conditions so as to provide a better understanding of the complex process of charge-carrier transport in natural as well as chemically modified DNA molecules. The investigations focused on the role of several features of DNA structure, namely the role of the negative charge at the backbone phosphate group and the related complex effects of counterions, and of the stacking interactions between the bases in Watson-Crick and other types of base pairs. The measurements have indicated that the best conductor is DNA in its biologically most relevant double-stranded form with Watson-Crick base pairs and charged phosphates equilibrated with counterions and water. All the studied modifications, including DNA with non-Watson-Crick base pairs, the abasic form, and especially the form with phosphate charges eliminated by chemical modifications, lower the conductivity of natural DNA.
利用扫描隧道显微镜（STM）技术研究了共价连接到金表面的DNA的导电性。在环境条件下测量了各种单链和双链的32个核苷酸长的DNA序列，以便更好地理解天然以及化学修饰的DNA分子中载流子传输的复杂过程。研究集中于DNA结构的几个特征的作用，即主链磷酸基团上负电荷的作用以及抗衡离子的相关复杂效应，以及沃森-克里克碱基对和其他类型碱基对中碱基之间的堆积相互作用。测量结果表明，导电性最佳的是具有沃森-克里克碱基对且带电荷的磷酸盐与抗衡离子和水平衡的生物相关性最强的双链形式的DNA。所有研究的修饰，包括具有非沃森-克里克碱基对的DNA、无碱基形式，特别是通过化学修饰消除磷酸盐电荷的形式，都会降低天然DNA的导电性。
