Chemistry and Biochemistry, Swarthmore College, 500 College Avenue, Swarthmore, PA 19081, USA.
Acta Crystallogr F Struct Biol Commun. 2023 Jun 1;79(Pt 6):144-150. doi: 10.1107/S2053230X23003977. Epub 2023 May 24.
The crystal structure of the G-rich human telomeric DNA Tel22 has been determined at 1.35 Å resolution in space group P6. Tel22 forms a non-canonical DNA structure called the G-quadruplex. The space group and unit-cell parameters are comparable to those in the crystal structures with PDB codes 6ip3 (1.40 Å resolution) and 1kf1 (2.15 Å resolution). The G-quadruplexes are highly similar in all of the structures. However, this structure of Tel22 displays clear density for polyethylene glycol and two potassium ions, which are located outside the ion channel in the G-quadruplex and play an important role in stabilizing the crystal contacts. In addition, 111 water molecules were identified (compared with 79 and 68 in PDB entries 6ip3 and 1kf1, respectively) that participate in intricate and extensive networks providing high stability to the G-quadruplex.
富含鸟嘌呤的人类端粒 DNA Tel22 的晶体结构已在 P6 空间群中以 1.35Å 的分辨率确定。Tel22 形成了一种称为 G-四链体的非经典 DNA 结构。该空间群和晶胞参数与具有 PDB 代码 6ip3（1.40Å 分辨率）和 1kf1（2.15Å 分辨率）的晶体结构相当。所有结构中的 G-四链体高度相似。然而，Tel22 的这种结构显示出明显的聚乙二醇和两个钾离子的密度，它们位于 G-四链体的离子通道之外，对稳定晶体接触起着重要作用。此外，还鉴定了 111 个水分子（分别与 PDB 条目 6ip3 和 1kf1 中的 79 个和 68 个相比），它们参与了复杂而广泛的网络，为 G-四链体提供了高度的稳定性。
