High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031, China.
University of Science and Technology of China, Hefei 230026, China.
Nucleic Acids Res. 2019 Feb 20;47(3):1544-1556. doi: 10.1093/nar/gky1167.
Aside from classical loops among G-quadruplexes, the unique leaped V-shape scaffold spans over three G-tetrads, without any intervening residues. This scaffold enables a sharp reversal of two adjacent strand directions and simultaneously participates in forming the G-tetrad core. These features make this scaffold itself distinctive and thus an essentially more accessible target. As an alternative to the conventional antisense method using a complementary chain, forming an intermolecular G-quadruplex from two different oligomers, in which the longer one as the target is captured by a short G-rich fragment, could be helpful for recognizing G-rich sequences and structural motifs. However, such an intermolecular leaped V-shape G-quadruplex consisting of DNA oligomers of quite different lengths has not been evaluated. Here, we present the first nuclear magnetic resonance (NMR) study of an asymmetric intermolecular leaped V-shape G-quadruplex assembled between an Oxytricha nova telomeric sequence d(G2T4G4T4G4) and a single G-tract fragment d(TG4A). Furthermore, we explored the selectivity of this short fragment as a potential probe, examined the kinetic discrimination for probing a specific mutant, and proposed the key sequence motif d(G2NG3NG4) essential for building the leaped V-shape G-quadruplexes.
除了经典的 G-四链体环，独特的跨越式 V 形支架跨越三个 G-四联体，没有任何中间残基。该支架能够急剧反转两个相邻链的方向，并同时参与形成 G-四联体核心。这些特征使该支架本身具有独特性，因此成为更具吸引力的靶标。作为一种替代传统反义方法的方法，使用两条不同寡核苷酸形成分子间 G-四链体，其中较长的一条作为靶标被短的富含 G 的片段捕获，这可能有助于识别富含 G 的序列和结构基序。然而，这种由 DNA 寡核苷酸组成的不同长度的分子间跨越式 V 形 G-四链体尚未得到评估。在这里，我们首次进行了核磁共振（NMR）研究，研究了一种不对称的分子间跨越式 V 形 G-四链体，该结构由棘尾虫端粒序列 d(G2T4G4T4G4)和单个 G-链片段 d(TG4A)组装而成。此外，我们还探索了该短片段作为潜在探针的选择性，考察了对特定突变体进行探测的动力学区分，并提出了构建跨越式 V 形 G-四链体所必需的关键序列基序 d(G2NG3NG4)。
