In this work, we have investigated the strength and mechanism of amifampridine (3,4-Diaminopyridine/3,4-DAP) interaction with calf thymus DNA (ct-DNA). The existence and the strength of interaction are evaluated using circular dichroism (CD), UV–vis absorption, and differential pulse voltammogram studies. Results from UV–vis absorption technique indicate that amifampridine can significantly interact with DNA through a binding constant of K_b = 1.66 × 10⁵ M⁻¹ at 298 K. The mechanism of the interaction between amifampridine and DNA is also studied using ionic effect investigations, competitive fluorescence experiments, viscosity measurements, and molecular docking studies. The viscosity results indicate that amifampridine can bind to DNA via intercalation binding mode. Competitive fluorescence experiments using Acridine Orange (AO) and Hoechst 33258 (HO) probes also reveal that amifampridine binds to DNA via an intercalation mode of binding. Finally, the molecular docking studies also suggest that amifampridine tends to bind with the G–C rich region of DNA.

中文翻译：

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探索氨苯吡啶与小牛胸腺DNA结合的强度和机制

在这项工作中，我们研究了氨苯吡啶（3,4-二氨基吡啶/ 3,4-DAP）与小牛胸腺DNA（ct-DNA）相互作用的强度和机理。使用圆二色性（CD），紫外可见吸收和微分脉冲伏安图研究评估了相互作用的存在和强度。紫外可见吸收技术的结果表明，氨苯吡啶可通过K _b  = 1.66×10 ⁵ M ^-1的结合常数与DNA发生显着相互作用在298 K时。使用离子效应研究，竞争性荧光实验，粘度测量和分子对接研究，也研究了氨苯吡啶与DNA之间的相互作用机理。粘度结果表明，氨if啶可以通过嵌入结合模式与DNA结合。使用A啶橙（AO）和Hoechst 33258（HO）探针进行的竞争性荧光实验还表明，氨苯吡啶通过结合的嵌入模式与DNA结合。最后，分子对接研究还表明，氨苯吡啶往往会与富含G–C的DNA结合。