Institute of Chemical Biology and Fundamental Medicine, SB RAS, 8 Lavrentiev Avenue, Novosibirsk, 630090, Russia; Novosibirsk State University, 2 Pirogova St., Novosibirsk, 630090, Russia.
Institute of Chemical Biology and Fundamental Medicine, SB RAS, 8 Lavrentiev Avenue, Novosibirsk, 630090, Russia.
Biochem Biophys Res Commun. 2019 Jun 11;513(4):807-811. doi: 10.1016/j.bbrc.2019.04.024. Epub 2019 Apr 15.
Recently, a new type of nucleic acid analogues with modified phosphate group, namely, phosphoryl guanidine oligonucleotides, has been described. In the present work, we assess the difference between diastereomers of a mono-substituted phosphoryl guanidine oligonucleotide and analyze their resistance to nuclease digestion. Individual diastereomers ('fast' and 'slow') of a trideoxynucleotide d (TpCpA) were isolated by reverse-phase HPLC. Snake venom phosphodiesterase digestion showed that the native trideoxynucleotide was fully degraded after 30 min, whereas both 'fast' and 'slow' diastereomers of d (TpCpA) were not completely digested even after 7 days. UV and CD spectra revealed similarities in the structure of the diastereomers. Structural analysis by 1D and 2D NMR spectroscopy also uncovered significant similarity in the properties of Rp and Sp diastereomers. Structural analysis of nuclear Overhauser effect spectroscopy (NOESY) data and restrained molecular dynamics methods showed very flexible single-stranded oligonucleotide structures. Detailed computational analysis of restraint penalty energies via restrained molecular dynamics simulations with the 2D NMR interproton distance data allowed us to conclude that most likely, the 'fast' isomer is the Sp diastereomer, and the 'slow' isomer is the Rp diastereomer.
最近，一种新型的磷酸基团修饰的核酸类似物，即磷酰胍寡核苷酸，已经被描述。在本工作中，我们评估了单取代磷酰胍寡核苷酸的非对映异构体之间的差异，并分析了它们对核酸酶消化的抗性。通过反相 HPLC 分离出十三核苷酸 d(TpCpA)的单个非对映异构体（'快'和'慢'）。蛇毒磷酸二酯酶消化表明，天然的十三核苷酸在 30 分钟内完全降解，而 d(TpCpA)的'快'和'慢'两种非对映异构体即使在 7 天后也没有完全消化。紫外和 CD 光谱显示非对映异构体的结构相似。通过一维和二维 NMR 光谱的结构分析也揭示了 Rp 和 Sp 非对映异构体的性质具有显著的相似性。通过核 Overhauser 效应光谱（NOESY）数据和约束分子动力学方法的结构分析表明，单链寡核苷酸结构非常灵活。通过约束分子动力学模拟和二维 NMR 质子间距离数据对约束罚能进行详细的计算分析，我们得出结论，'快'异构体很可能是 Sp 非对映异构体，'慢'异构体是 Rp 非对映异构体。
