Varizhuk Irina V, Stomakhin Andrey A, Ermolaeva Anna N, Petrova Ksenia V, Surzhikov Sergei A, Kolganova Natalia A, Timofeev Edward N
Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 32 Vavilov St., 119991 Moscow, Russian Federation.
Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 32 Vavilov St., 119991 Moscow, Russian Federation.
Int J Biol Macromol. 2025 Aug;319(Pt 4):145705. doi: 10.1016/j.ijbiomac.2025.145705. Epub 2025 Jul 1.
DNA and RNA G-quadruplexes (GQ) are non-canonical G-rich four-stranded structures with proven important roles in major cellular events. DNA GQs are highly polymorphic. Their topology and G-tetrad architecture are strongly influenced by numerous factors. Notable variations in topology and stability between different GQs arise partially from glycosidic bond syn-anti conformational isomerism. The use of unnatural nucleotide analogues with a preferred syn or anti configuration is an efficient approach to control GQ folding, G-tetrad architecture, and stability. Alpha-nucleosides are known to adopt preferably anti-configuration of glycosidic bond. Selective modification of GQs with alpha-2'-deoxyguanosine (αdG) provides a useful tool to manipulate GQ structural parameters and stability. In the GQ core, unnatural αdG residues mimic invariant syn-dG nucleotides and thus drastically reduce the range of possible conformational rearrangements. Understanding the role of αdG modification in controlling GQ architecture and stability requires further biophysical and structural studies of modified GQs. In this paper, we report the design and biophysical characterization of anti-parallel three-layer GQs with αdG-modified G-tetrads of the same polarity. Furthermore, we investigate the therapeutic potential of modified G-rich oligonucleotides in the context of induced formation of αdG-modified anti-parallel GQ. A highly specific termination of primer extension at selected position was induced at a short G3 run in the template strand via guided association with the three segment G-rich modified oligonucleotide.
DNA和RNA G-四链体（GQ）是富含鸟嘌呤的非经典四链结构，在主要细胞事件中具有重要作用。DNA GQ具有高度多态性。它们的拓扑结构和G-四联体结构受到多种因素的强烈影响。不同GQ之间拓扑结构和稳定性的显著差异部分源于糖苷键顺反构象异构。使用具有优选顺式或反式构型的非天然核苷酸类似物是控制GQ折叠、G-四联体结构和稳定性的有效方法。已知α-核苷优选采用糖苷键的反式构型。用α-2'-脱氧鸟苷（αdG）对GQ进行选择性修饰，为操纵GQ结构参数和稳定性提供了有用的工具。在GQ核心中，非天然αdG残基模拟不变的顺式dG核苷酸，从而大大减少了可能的构象重排范围。了解αdG修饰在控制GQ结构和稳定性中的作用需要对修饰后的GQ进行进一步的生物物理和结构研究。在本文中，我们报告了具有相同极性的αdG修饰G-四联体的反平行三层GQ的设计和生物物理表征。此外，我们在诱导形成αdG修饰的反平行GQ的背景下研究了修饰的富含G的寡核苷酸的治疗潜力。通过与三段富含G的修饰寡核苷酸的引导结合，在模板链中的短G3序列处诱导引物延伸在选定位置高度特异性终止。
