Karwowski Boleslaw T
Food Science Department, Medical University of Lodz, ul. Muszynskiego 1, 90-151 Lodz, Poland.
Phys Chem Chem Phys. 2015 Sep 7;17(33):21507-16. doi: 10.1039/c5cp01382h. Epub 2015 Jul 29.
In this study the influence of the phosphorothioate internucleotide bond on the electronic properties of single and double-stranded short nucleotides has been investigated at the M06-2X/6-31+G** level of theory in the gaseous phase. Due to the chirality of the phosphorus atom in a phosphorothioate (PT) internucleotide diester bond, the adiabatic/vertical mode of electron affinity/ionization potential, spin density and molecular orbital distribution, as well as structural analysis were taken under consideration for the single stranded (ss) R(P) and S(P) diastereomers of d[G(PS)G] and for double stranded (ds) d[G(PS)G]d[C(PO)C], in comparison with the corresponding parent phosphate compounds. Moreover, the excitation states, HOMO and LUMO energies were calculated using a TD-DFT methodology at the M06-2X/6-31+G//M06-2X/6-31++G* level of theory in the aqueous phase. The obtained results show that the PT plays a significant role in the case of ss-oligonucleotides, and to a much smaller extent in ds-oligomers.
在本研究中，已在气相中M06 - 2X/6 - 31 + G理论水平下研究了硫代磷酸酯核苷酸间键对单链和双链短核苷酸电子性质的影响。由于硫代磷酸酯（PT）核苷酸间二酯键中磷原子的手性，对d[G(PS)G]的单链（ss）R(P)和S(P)非对映异构体以及双链（ds）d[G(PS)G]d[C(PO)C]，考虑了电子亲和能/电离势的绝热/垂直模式、自旋密度和分子轨道分布以及结构分析，并与相应的母体磷酸酯化合物进行了比较。此外，在水相中使用TD - DFT方法在M06 - 2X/6 - 31 + G//M06 - 2X/6 - 31++G*理论水平下计算了激发态、最高占据分子轨道（HOMO）和最低未占据分子轨道（LUMO）能量。所得结果表明，PT在单链寡核苷酸的情况下起重要作用，而在双链寡聚物中的作用要小得多。
