Kletsov Aleksey A, Glukhovskoy Evgeny G, Chumakov Aleksey S, Ortiz Joseph V
Educational Research Institute of Nanostructures and Biosystems, Saratov State University, Astrakhanskaya 83, Saratov, Russia; Department of Nano- and Biomedical Technologies, Saratov State University, Astrakhanskaya 83, Saratov, Russia.
Educational Research Institute of Nanostructures and Biosystems, Saratov State University, Astrakhanskaya 83, Saratov, Russia; Department of Nano- and Biomedical Technologies, Saratov State University, Astrakhanskaya 83, Saratov, Russia.
Biochim Biophys Acta. 2016 Jan;1860(1 Pt A):140-5. doi: 10.1016/j.bbagen.2015.10.013. Epub 2015 Oct 23.
The conduction properties of DNA molecule, particularly its transverse conductance (electron transfer through nucleotide bridges), represent a point of interest for DNA chemistry community, especially for DNA sequencing. However, there is no fully developed first-principles theory for molecular conductance and current that allows one to analyze the transverse flow of electrical charge through a nucleotide base.
We theoretically investigate the transverse electron transport through all four DNA nucleotide bases by implementing an unbiased ab initio theoretical approach, namely, the electron propagator theory.
The electrical conductance and current through DNA nucleobases (guanine [G], cytosine [C], adenine [A] and thymine [T]) inserted into a model 1-nm Ag-Ag nanogap are calculated. The magnitudes of the calculated conductance and current are ordered in the following hierarchies: gA>gG>gC>gT and IG>IA>IT>IC correspondingly. The new distinguishing parameter for the nucleobase identification is proposed, namely, the onset bias magnitude. Nucleobases exhibit the following hierarchy with respect to this parameter: Vonset(A)<Vonset(T)<Vonset(G)<Vonset(C).
The difference in current magnitudes and onset voltages implies the possibility of nucleobases electrical identification by virtue of DNA translocation through an electrode-equipped nanopore.
The results represent interest for the theorists and practitioners in the field of third generation sequencing techniques as well as in the field of DNA chemistry.
DNA分子的传导特性，尤其是其横向电导（通过核苷酸桥的电子转移），是DNA化学领域，特别是DNA测序领域的一个研究热点。然而，目前还没有一个完善的第一性原理理论来分析分子电导和电流，从而无法对电荷通过核苷酸碱基的横向流动进行分析。
我们通过采用一种无偏的从头算理论方法，即电子传播子理论，从理论上研究了通过所有四种DNA核苷酸碱基的横向电子传输。
计算了插入到1纳米银-银纳米间隙模型中的DNA核碱基（鸟嘌呤[G]、胞嘧啶[C]、腺嘌呤[A]和胸腺嘧啶[T]）的电导和电流。计算得到的电导和电流大小按以下顺序排列：gA>gG>gC>gT和IG>IA>IT>IC。提出了用于碱基识别的新的区分参数，即起始偏置大小。碱基在该参数方面表现出以下顺序：Vonset(A)<Vonset(T)<Vonset(G)<Vonset(C)。
电流大小和起始电压的差异意味着通过配备电极的纳米孔进行DNA易位来对核碱基进行电学识别的可能性。
这些结果对于第三代测序技术领域以及DNA化学领域的理论家和从业者具有重要意义。
