Rupreo Vibeizonuo, Das Deepak, Yanthan Senchumbeni, Bhattacharyya Jhimli
Department of Chemistry, National Institute of Technology Nagaland, Chumukedima, Nagaland 797103, India.
J Phys Chem B. 2025 Jan 16;129(2):637-649. doi: 10.1021/acs.jpcb.4c07948. Epub 2025 Jan 7.
As one of nature's most fundamental blueprints and due to its critical role in life processes, DNA has naturally become the cornerstone of numerous research efforts. One particularly intriguing area of study is understanding how small molecules interact with nucleic acids. In this study, we investigated the interaction between the plant-derived indole alkaloid Raubasine (Ajmalicine; AJM) and Salmon Testes (ST) DNA using biophysical and computational techniques. A hyperchromic shift in the fluorescence intensity indicated the effective binding of AJM to ST DNA. The binding constant was in the order of 10 M with a single preferential binding mode. Thermodynamic analysis revealed that exothermic binding was driven by positive entropy and negative enthalpy. The salt-dependent fluorescence analysis indicates the involvement of nonpolyelectrolytic forces in the interaction. Studies of iodide quenching, urea denaturation, dye displacement, and molecular docking further support that AJM binds to ST DNA through groove binding. Structural perturbation of DNA was evident from circular dichroism. The stability of the AJM-DNA complex was confirmed by molecular dynamics simulations. Prolonged elevated blood glucose levels induce nonenzymatic glycation of DNA, resulting in DNA-AGE (advanced glycation end-products) formation and free radical production, which disrupts the DNA structure. We explored ST-DNA glycation and its suppression by AJM. DNA-AGEs in vitro were characterized using UV-vis and fluorescence spectroscopy. The inhibition of glycation by AJM was assessed through changes in AGEs fluorescence intensity, gel electrophoresis patterns, and antioxidant activity, highlighting its ability to target glycated sites or neutralize free radicals generated during glycation. Our findings reveal AJM's potential to prevent the formation of AGEs, which may offer promising avenues for targeted therapies against glycation-related diseases such as diabetes, neurodegeneration, and cancer.
作为自然界最基本的蓝图之一，由于其在生命过程中的关键作用，DNA自然成为众多研究工作的基石。一个特别有趣的研究领域是了解小分子如何与核酸相互作用。在本研究中，我们使用生物物理和计算技术研究了植物来源的吲哚生物碱萝巴新（阿吗灵；AJM）与鲑鱼精巢（ST）DNA之间的相互作用。荧光强度的增色效应表明AJM与ST DNA有效结合。结合常数约为10 M，具有单一的优先结合模式。热力学分析表明，放热结合由正熵和负焓驱动。盐依赖性荧光分析表明非聚电解质力参与了相互作用。碘化物猝灭、尿素变性、染料置换和分子对接研究进一步支持AJM通过沟槽结合与ST DNA结合。圆二色性表明DNA的结构发生了扰动。分子动力学模拟证实了AJM-DNA复合物的稳定性。长期升高的血糖水平会诱导DNA的非酶糖基化，导致DNA-AGE（晚期糖基化终产物）形成和自由基产生，从而破坏DNA结构。我们研究了ST-DNA糖基化及其被AJM抑制的情况。使用紫外可见光谱和荧光光谱对体外DNA-AGEs进行了表征。通过AGEs荧光强度、凝胶电泳图谱和抗氧化活性的变化评估了AJM对糖基化的抑制作用，突出了其靶向糖基化位点或中和糖基化过程中产生的自由基的能力。我们的研究结果揭示了AJM预防AGEs形成的潜力，这可能为针对糖尿病、神经退行性疾病和癌症等糖基化相关疾病的靶向治疗提供有前景的途径。
