a Department of Chemistry , Aligarh Muslim University , Aligarh , 202 002 , Uttar Pradesh , India.
b Interdisciplinary Biotechnology Unit , Aligarh Muslim University , Aligarh , 202 002 , Uttar Pradesh , India.
J Biomol Struct Dyn. 2018 Oct;36(13):3362-3375. doi: 10.1080/07391102.2017.1388284. Epub 2017 Oct 23.
Intermolecular interaction study of human serum albumin (HSA) with two anthraquinones i.e. danthron and quinizarin has been performed through fluorescence, UV-vis and CD spectroscopy along with docking analysis. The titration of drugs into HSA solution brought about the quenching of fluorescence emission by way of complex formation. The binding constants were found to be 1.51 × 10 L mol and 1.70 × 10 L mol at λ = 280 nm while at λ = 295 nm, the values of binding constants were 1.81 × 10 L mol and 1.90 × 10 L mol which hinted toward binding of both the drugs in the vicinity of subdomain IIA. Different temperature study revealed the presence of static quenching mechanism. Moreover, more effective quenching of the fluorescence emission was observed at λ = 295 nm which also suggested that both the drug molecule bind nearer to Trp-214. Thermodynamic parameters showed that hydrophobic interaction was the major force behind the binding of drugs. The UV-vis spectroscopy testified the formation of complex in both the systems and primary quenching mechanism as static one. The changes in secondary structure and α-helicity in both the systems were observed by circular dichroism spectroscopy. Furthermore, molecular docking analysis predicted the probable binding site of drugs in subdomain IIA of HSA molecule. The types of amino acid residues surrounding the drug molecule advocated that van der Waals forces, hydrophobic forces and electrostatic forces played a vital role in the stabilization of drug-protein complex formed.
通过荧光、紫外-可见和圆二色光谱以及对接分析，研究了人血清白蛋白（HSA）与两种蒽醌类药物丹蒽酮和喹啉嗪的分子间相互作用。药物与 HSA 溶液的滴定导致荧光发射的猝灭，这是通过复合物形成实现的。在 λ = 280 nm 时，结合常数分别为 1.51×10^4 和 1.70×10^4 L mol^-1，而在 λ = 295 nm 时，结合常数分别为 1.81×10^4 和 1.90×10^4 L mol^-1，这表明两种药物都在亚域 IIA 附近结合。不同温度的研究表明存在静态猝灭机制。此外，在 λ = 295 nm 观察到荧光发射的更有效猝灭，这也表明两种药物分子更靠近色氨酸 214 结合。热力学参数表明，疏水相互作用是药物结合的主要驱动力。紫外-可见光谱证明了两种体系中复合物的形成和作为静态的主要猝灭机制。圆二色光谱观察到两种体系中二级结构和α-螺旋性的变化。此外，分子对接分析预测了药物在 HSA 分子亚域 IIA 中的可能结合位点。围绕药物分子的氨基酸残基类型表明，范德华力、疏水相互作用力和静电相互作用力在稳定形成的药物-蛋白复合物中发挥了重要作用。
