A novel naphthalene diimde analogue (NDI) equipped at the imide positions with two guanidinio-carbonyl-pyrrole (GCP) pendant arms interacted significantly stronger with ds-DNA at pH 5 than at pH 7, due to reversible protonation of the GCP arms. This was consequence of a pH-switchable threading intercalation into ds-DNAs only at pH 5, while at neutral conditions (pH 7) NDI-GCP₂ switched to the DNA minor groove binding. Intriguingly, NDI-GCP₂ was at both pH values studied bound to the ds-RNA major groove, still showing a higher affinity and thermal denaturation effect at pH 5 due to GCP protonation. At excess over the DNA/RNA conjugate NDI-GCP₂ showed also aggregation along the ds-polynucleotide and AFM and DLS demonstrated that NDI-GCP₂ has pronounced ds-DNA condensation ability.

中文翻译：

---

萘二酰亚胺双胍基羰基吡咯作为pH值可转换的穿线DNA嵌入剂

一种新型的萘二酰亚胺类似物（NDI），在酰亚胺位置配备了两个胍基-羰基-吡咯（GCP）侧链，在pH 5时与ds-DNA相互作用比在pH 7时显着强，这是由于GCP臂的可逆质子化。这是仅在pH 5时，pH可调线程插入ds-DNA的结果，而在中性条件（pH 7）下，NDI-GCP ₂转换为DNA小沟结合。有趣的是，NDI-GCP ₂的两个pH值均与ds-RNA主沟结合，但由于GCP质子化，在pH 5时仍显示出更高的亲和力和热变性作用。超过DNA / RNA偶联物的NDI-GCP ₂也沿ds-多核苷酸聚集，AFM和DLS证实NDI-GCP ₂ 具有明显的ds-DNA缩合能力。