J Am Chem Soc. 2013 Nov 6;135(44):16468-77. doi: 10.1021/ja406737n.
Pyrrole–imidazole (PI) polyamides bind to the minor groove of DNA in a sequence-specific manner without causing denaturation of DNA. To visualize telomeres specifically, tandem hairpin PI polyamides conjugated with a fluorescent dye have been synthesized, but the study of telomeres using these PI polyamides has not been reported because of difficulties synthesizing these tandem hairpin PI polyamides. To synthesize tandem hairpin PI polyamides more easily, we have developed new PI polyamide fragments and have used them as units in Fmoc solid-phase peptide synthesis. Using this new method, we synthesized four fluorescent polyamide probes for the human telomeric repeat TTAGGG, and we examined the binding affinities and specificities of the tandem hairpin PI polyamides, the UV–vis absorption and fluorescence spectra of the fluorescent polyamide probes, and telomere staining in mouse MC12 and human HeLa cells. The polyamides synthesized using the new method successfully targeted to human and mouse telomeres under mild conditions and allow easier labeling of telomeres in the cells while maintaining the telomere structure. Using the fluorescent polyamides, we demonstrated that the telomere length at a single telomere level is related to the abundance of TRF1 protein, a shelterin complex component in the telomere.
吡咯并咪唑（PI）聚酰胺以序列特异性方式结合到 DNA 的小沟中，而不会导致 DNA 变性。为了特异性地可视化端粒，已经合成了与荧光染料缀合的串联发夹 PI 聚酰胺，但由于合成这些串联发夹 PI 聚酰胺存在困难，因此尚未报道使用这些 PI 聚酰胺研究端粒。为了更容易合成串联发夹 PI 聚酰胺，我们开发了新的 PI 聚酰胺片段，并将其用作 Fmoc 固相肽合成中的单元。使用这种新方法，我们合成了用于人类端粒重复序列 TTAGGG 的四个荧光聚酰胺探针，并研究了串联发夹 PI 聚酰胺的结合亲和力和特异性、荧光聚酰胺探针的紫外-可见吸收和荧光光谱以及在小鼠 MC12 和人 HeLa 细胞中端粒的染色。使用新方法合成的聚酰胺在温和条件下成功靶向人类和小鼠端粒，并允许在保持端粒结构的同时更容易地标记细胞中端粒。使用荧光聚酰胺，我们证明了单个端粒水平的端粒长度与端粒保护复合物成分 TRF1 蛋白的丰度有关。
