Slovenian NMR Center, National Institute of Chemistry, 1000 Ljubljana, Slovenia.
University of Ljubljana, Faculty of Chemistry and Chemical Technology, 1000 Ljubljana, Slovenia.
Nucleic Acids Res. 2020 Mar 18;48(5):2749-2761. doi: 10.1093/nar/gkaa058.
GCn and GCnCG, where n = (G2AG4AG2), fold into well-defined, dimeric G-quadruplexes with unprecedented folding topologies in the presence of Na+ ions as revealed by nuclear magnetic resonance spectroscopy. Both G-quadruplexes exhibit unique combination of structural elements among which are two G-quartets, A(GGGG)A hexad and GCGC-quartet. Detailed structural characterization uncovered the crucial role of 5'-GC ends in formation of GCn and GCnCG G-quadruplexes. Folding in the presence of 15NH4+ and K+ ions leads to 3'-3' stacking of terminal G-quartets of GCn G-quadruplexes, while 3'-GC overhangs in GCnCG prevent dimerization. Results of the present study expand repertoire of possible G-quadruplex structures. This knowledge will be useful in DNA sequence design for nanotechnological applications that may require specific folding topology and multimerization properties.
GCn 和 GCnCG（其中 n = (G2AG4AG2)）在钠离子存在下通过核磁共振波谱学显示出具有前所未有的折叠拓扑结构的明确、二聚体 G-四链体。两种 G-四链体都具有独特的结构元素组合，其中包括两个 G-四联体、一个 A(GGGG)A 六联体和 GCGC-四联体。详细的结构特征揭示了 5'-GC 末端在 GCn 和 GCnCG G-四链体形成中的关键作用。在 15NH4+ 和 K+ 离子存在下折叠导致 GCn G-四链体的末端 G-四联体 3'-3' 堆积，而 GCnCG 中的 3'-GC 突出阻止二聚化。本研究的结果扩展了可能的 G-四链体结构的范围。这些知识将有助于 DNA 序列设计，用于可能需要特定折叠拓扑和多聚化特性的纳米技术应用。
