We have developed a dual-app nucleoside analog, 5-selenophene-modified 2′-deoxyuridine (^SedU), to probe the structure and ligand-binding properties of a G-rich segment present in the long terminal repeat (LTR) of the HIV-1 proviral DNA promoter region. The nucleoside probe is made of an environment-responsive fluorophore and X-ray crystallography phasing label (Se atom). ^SedU incorporated into LTR-IV sequence, fluorescently reports the formation of G-quadruplex (GQ) structure without affecting the native fold. Further, using the environment sensitivity of the probe, a fluorescence assay was designed to estimate the binding affinity of small molecule ligands to the GQ motif. An added feature of this probe system is that it would enable direct correlation of structure and recognition properties in solution and atomic level by using a combination of fluorescence and X-ray crystallography techniques.

我们开发了一种双应用核苷类似物，5-硒酚修饰的 2'-脱氧尿苷 ( ^Se dU)，以探测存在于长末端重复 (LTR) 中的富含 G 片段的结构和配体结合特性。 HIV-1 前病毒 DNA 启动子区域。核苷探针由环境响应荧光团和 X 射线晶体学定相标记（Se 原子）制成。^硒dU 并入 LTR-IV 序列，荧光报告 G-四链体 (GQ) 结构的形成，而不影响天然折叠。此外，利用探针的环境敏感性，设计了一种荧光测定来估计小分子配体与 GQ 基序的结合亲和力。该探针系统的另一个特点是，它可以通过结合使用荧光和 X 射线晶体学技术，在溶液和原子水平上实现结构和识别特性的直接关联。