Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, 202002, Uttar Pradesh, India.
Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, P.O. Box 2457, Riyadh 11451, Saudi Arabia.
Int J Biol Macromol. 2018 Feb;107(Pt B):1414-1421. doi: 10.1016/j.ijbiomac.2017.10.006. Epub 2017 Oct 5.
We have studied the binding of busulfan (BN) to human serum albumin (HSA) at physiological pH 7.4 by using fluorescence, UV-vis and circular dichroism (CD) spectroscopic tools, as well as dynamic light scattering (DLS) measurements and molecular simulation approaches. HSA fluorescence quenching experiments showed that BN reduces the HSA native fluorescence intensity through the static mechanism. In addition, a single binding site on the HSA is occupied by BN with a binding constant at 298K of 1.84×10M. The enthalpy change (ΔH) and entropy change (ΔS) of BN-HSA interaction were calculated as -1.40kcalmol and +10.14calmolK respectively, which suggest the possible interaction mode as hydrophobic and hydrogen bonding. Moreover, the secondary structure alteration of HSA following its complexation with BN was studied and showed that α-helical content of HSA gets increased on interacting with BN. Ligand binding site to HSA was further investigated by site-specific markers in fluorescence measurements as well molecular modeling approach which indicated that BN bind to the nearby sudlow site II of HSA through hydrophobic as well as hydrogen bonding interaction. The present study will be helpful for understanding the binding mechanism of BN to human serum albumin.
我们在生理 pH 值 7.4 下使用荧光、紫外-可见和圆二色性（CD）光谱学工具以及动态光散射（DLS）测量和分子模拟方法研究了白消安（BN）与人血清白蛋白（HSA）的结合。HSA 荧光猝灭实验表明，BN 通过静态机制降低 HSA 的天然荧光强度。此外，BN 占据 HSA 上的一个单一结合位点，在 298K 时的结合常数为 1.84×10M。BN-HSA 相互作用的焓变（ΔH）和熵变（ΔS）分别计算为-1.40kcalmol 和+10.14calmolK，这表明可能的相互作用模式为疏水和氢键。此外，还研究了 BN 与 HSA 复合后 HSA 的二级结构变化，结果表明 HSA 的α-螺旋含量在与 BN 相互作用时增加。荧光测量中的位点特异性标记和分子建模方法进一步研究了配体与 HSA 的结合位点，表明 BN 通过疏水和氢键相互作用结合到 HSA 的附近 Sudlow 位点 II。本研究将有助于理解 BN 与人血清白蛋白的结合机制。
