Phosphoryl guanidine oligonucleotides (PGOs) are promising uncharged analogs of nucleic acids and are used in a variety of applications. The importance of hydration is frequently ignored during the design of modified nucleic acid probes. Such hydrophobic modifications (phosphoryl guanidine) are expected to have a significant impact on the structure and thermal stability of the affected oligo with complementary nucleic acids. Here we aimed to investigate (by the osmotic stress method) hydration changes upon the formation of a duplex of a PGO with complementary DNA. According to our results, the presence of phosphoryl guanidines in one or both strands of a duplex only minimally affects hydration alterations under crowding conditions. The secondary structure of native and modified duplexes did not change significantly in the presence of ethanol, ethylene glycol, polyethylene glycol 200, or polyethylene glycol 1000. After the addition of a cosolvent, the thermodynamic stability of the PGO complexes changed in the same manner as that seen in a corresponding DNA duplex. The findings reported here and our previous studies form the basis for efficient use of PGOs in basic research and a variety of applications.

磷酰胍寡核苷酸 (PGO) 是很有前途的不带电荷的核酸类似物，可用于各种应用。在修饰核酸探针的设计过程中，水合作用的重要性经常被忽略。预计此类疏水修饰（磷酰胍）将对受影响的具有互补核酸的寡核苷酸的结构和热稳定性产生显着影响。在这里，我们旨在研究（通过渗透压力法）在形成具有互补 DNA 的 PGO 的双链体时水合变化。根据我们的结果，双链体的一条或两条链中磷酰胍的存在对拥挤条件下的水合变化影响很小。在乙醇存在下，天然和修饰双链体的二级结构没有显着变化，乙二醇、聚乙二醇 200 或聚乙二醇 1000。加入助溶剂后，PGO 复合物的热力学稳定性发生变化，与相应 DNA 双链体中所见的变化方式相同。这里报告的发现和我们之前的研究构成了在基础研究和各种应用中有效使用 PGO 的基础。