Department of Medical Biotechnology, Yeungnam University, 280 Daehak-ro, Gyeongsan, Gyeongbuk 38541, Korea.
Department of Biophysics, All India Institute of Medical Sciences, Ansari nagar, New Delhi 110029, India.
Int J Mol Sci. 2019 Feb 3;20(3):662. doi: 10.3390/ijms20030662.
Cyclobenzaprine hydrochloride (CBH) is a well-known muscle relaxant that is widely used to relieve muscle spasms and other pain associated with acute musculoskeletal conditions. In this study, we elucidated the binding characteristics of this muscle relaxant to human serum albumin (HSA). From a pharmaceutical and biochemical viewpoint, insight into the structure, functions, dynamics, and features of HSA-CBH complex holds great importance. The binding of CBH with this major circulatory transport protein was studied using a combination of biophysical approaches such as UV-VIS absorption, fluorescence quenching, and circular dichroism (CD) spectroscopy. Various techniques, molecular docking and molecular dynamics, were also used to gain deeper insight into the binding. A reduction in the fluorescence intensities of HSA-CBH complex with a constant increase in temperature, revealed the static mode of protein fluorescence quenching upon CBH addition, which confirmed the formation of the HSA-CBH ground state complex. The alteration in the UV-VIS and far-UV CD spectrum indicated changes in both secondary and tertiary structures of HSA upon binding of CBH, further proving CBH binding to HSA. The analysis of thermodynamic parameters ∆H° and ∆S° showed that binding of CBH to HSA was dominated by intermolecular hydrophobic forces. The results of the molecular docking and molecular dynamics simulation studies also confirmed the stability of the complex and supported the experimental results.
盐酸环苯扎林（CBH）是一种众所周知的肌肉松弛剂，广泛用于缓解与急性肌肉骨骼疾病相关的肌肉痉挛和其他疼痛。在这项研究中，我们阐明了这种肌肉松弛剂与人血清白蛋白（HSA）的结合特性。从药物和生化角度来看，深入了解 HSA-CBH 复合物的结构、功能、动力学和特征非常重要。使用紫外可见吸收、荧光猝灭和圆二色性（CD）光谱等多种物理化学方法研究了 CBH 与这种主要的循环转运蛋白的结合。还使用了分子对接和分子动力学等技术，以更深入地了解结合情况。随着温度的恒定升高，HSA-CBH 复合物的荧光强度降低，表明 CBH 加入时蛋白质荧光猝灭的静态模式，证实了 HSA-CBH 基态复合物的形成。紫外可见和远紫外 CD 光谱的变化表明，CBH 结合后 HSA 的二级和三级结构都发生了变化，进一步证明了 CBH 与 HSA 的结合。热力学参数 ∆H°和 ∆S°的分析表明，CBH 与 HSA 的结合主要由分子间疏水作用力主导。分子对接和分子动力学模拟研究的结果也证实了复合物的稳定性，并支持了实验结果。
