Marzano Maria, Nolli Maria Grazia, D'Errico Stefano, Falanga Andrea Patrizia, Terracciano Monica, Dardano Principia, De Stefano Luca, Piccialli Gennaro, Borbone Nicola, Oliviero Giorgia
Dipartimento di Farmacia, Università degli Studi di Napoli Federico II Via Domenico Montesano 49 80131 Napoli Italy
Institute of Applied Sciences and Intelligent Systems "Eduardo Caianiello", Unit of Naples, National Research Council Naples 80131 Italy.
RSC Adv. 2025 May 29;15(23):17933-17945. doi: 10.1039/d5ra01033k.
This study introduces a novel class of highly lipophilic DNA G-quadruplexes (G4s) obtained by installing the lipophilic -butyldiphenylsilyl group (TBDPS) at both ends of 5'-CG -3'-3'-G C-5' oligonucleotides (ONs), where = 1 or 2, featuring a 3'-3' inversion of polarity, thus obtaining symmetric (TBDPS-5'-CG -3'-3'-G C-5'-TBDPS) lipophilic G4s after annealing in K-containing buffer. The new 5'-bis-conjugated TBDPS-ONs were synthesized using a tailored solid-phase approach, where the first nucleoside (dC) was linked to the polymeric support the exocyclic amino group of the nucleobase. The effect of the presence of the TBDPS groups on G4 formation, stability, and propensity to form supramolecular G4 aggregates was assessed using H NMR, circular dichroism (CD), polyacrylamide gel electrophoresis (PAGE), scanning electron microscopy (SEM), dynamic light scattering (DLS), and atomic force microscopy (AFM) analyses. The results demonstrate that the presence of four TBDPS groups at the 5'-ends of the G4 strands enhances the stability of the G4s, enabling their formation even at low K concentration (20 mmol L). We report the formation of the smallest tetramolecular G4 observed to date, [(TBDPS-5'-CG-3'-3'-GC-5'-TBDPS)], which contains only two G-tetrads. Notably, this structure did not form when using the corresponding oligonucleotide sequence lacking the TBDPS groups, even at high K concentrations (up to 1 mol L). Furthermore, the lipophilic shells located at the 5'-faces of the G4 structures promote the formation of submicrometric coffee bean-like aggregates composed of G4 units. These novel lipophilic G4s exhibit two key features: high structural symmetry and a tunable balance between their lipophilic (TBDPS groups) and hydrophilic (oligonucleotide strands) moieties. This tunability allows for precise modulation of both the extent and the properties of the resulting supramolecular assemblies. These findings provide valuable insights into developing G4-based systems in DNA nanotechnology.
本研究介绍了一类新型的高亲脂性DNA G-四链体（G4s），通过在5'-CG -3'-3'-G C-5'寡核苷酸（ONs）的两端安装亲脂性的叔丁基二苯基硅烷基团（TBDPS）获得，其中 = 1或2，具有3'-3'极性反转，从而在含钾缓冲液中退火后得到对称的（TBDPS-5'-CG -3'-3'-G C-5'-TBDPS）亲脂性G4s。使用定制的固相方法合成了新的5'-双共轭TBDPS-ONs，其中第一个核苷（dC）通过核苷酸碱基的环外氨基连接到聚合物载体上。使用核磁共振氢谱（H NMR）、圆二色性（CD）、聚丙烯酰胺凝胶电泳（PAGE）、扫描电子显微镜（SEM）、动态光散射（DLS）和原子力显微镜（AFM）分析评估了TBDPS基团的存在对G4形成、稳定性和形成超分子G4聚集体倾向的影响。结果表明，G4链5'-端存在四个TBDPS基团增强了G4s的稳定性，即使在低K浓度（20 mmol L）下也能形成。我们报道了迄今为止观察到的最小的四分子G4的形成，即[(TBDPS-5'-CG-3'-3'-GC-5'-TBDPS)]，它仅包含两个G-四联体。值得注意的是，使用缺乏TBDPS基团的相应寡核苷酸序列时，即使在高K浓度（高达1 mol L）下也不会形成这种结构。此外，位于G4结构5'-面的亲脂性外壳促进了由G4单元组成的亚微米级咖啡豆状聚集体的形成。这些新型亲脂性G4s具有两个关键特征：高度的结构对称性以及它们的亲脂性（TBDPS基团）和亲水性（寡核苷酸链）部分之间的可调平衡。这种可调性允许对所得超分子组装体的程度和性质进行精确调节。这些发现为DNA纳米技术中基于G4的系统的开发提供了有价值的见解。
