State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, China.
Department of Biomedicine, New Zealand Institute of Natural Medicine Research, Auckland, New Zealand.
J Sci Food Agric. 2019 Jan 15;99(1):73-82. doi: 10.1002/jsfa.9144. Epub 2018 Jun 30.
Quinoline yellow (QY), a synthetic colourant widely used in the food industry, has caused extensive concerns because of its potentially harmful effects on human health. In the present work, the interactions between QY and human serum albumin (HSA) were characterized by multiple spectroscopic methods, a chemometric algorithm, and molecular modelling studies.
The concentration profiles and pure spectra obtained for the components (QY, HSA and QY-HSA complex) from analyses of the expanded UV-visible absorption data matrices by multivariate curve resolution alternating least squares confirmed the QY-HSA interaction process. QY quenched the fluorescence of HSA through formation of a QY-HSA complex that was stabilized by moderate affinity. Hydrophobic forces and hydrogen bonding play major roles in the binding of QY to HSA. Site-specific marker-induced displacement results suggest that QY binds to subdomain IIA of HSA. This was corroborated by the molecular docking results. Decreases in HSA surface hydrophobicity and free sulfhydryl group content indicate that QY causes a contraction of the peptide strand in HSA, hiding the hydrophobic patches of the protein. Analyses by UV-visible absorption, circular dichroism, and three-dimensional fluorescence spectroscopy found that QY causes microenvironmental perturbations around the fluorophores and secondary structure changes in HSA.
This work shows that QY binds to HSA, affecting its structural and functional properties, and provides new insights into the binding mechanism and a comprehensive understanding of the toxicity of QY to biological processes. © 2018 Society of Chemical Industry.
喹啉黄（QY）是一种广泛应用于食品工业的合成着色剂，由于其对人体健康可能产生的有害影响而引起了广泛关注。在本工作中，通过多种光谱方法、化学计量学算法和分子建模研究，研究了 QY 与人血清白蛋白（HSA）之间的相互作用。
通过对扩展的紫外-可见吸收数据矩阵进行多元曲线分辨交替最小二乘法分析，得到了各组分（QY、HSA 和 QY-HSA 复合物）的浓度曲线和纯光谱，证实了 QY-HSA 相互作用过程。QY 通过形成 QY-HSA 复合物猝灭了 HSA 的荧光，该复合物通过中等亲和力稳定。疏水作用力和氢键在 QY 与 HSA 的结合中起主要作用。基于位点特异性标记诱导置换的结果表明，QY 结合到 HSA 的 IIA 亚域。这一结果得到了分子对接结果的证实。HSA 表面疏水性和游离巯基含量的降低表明，QY 导致 HSA 中肽链收缩，隐藏了蛋白质的疏水区。通过紫外-可见吸收、圆二色性和三维荧光光谱分析发现，QY 引起了荧光团周围的微环境扰动和 HSA 二级结构的变化。
本工作表明，QY 与 HSA 结合，影响其结构和功能特性，为 QY 与生物过程的结合机制和综合毒性提供了新的认识。 © 2018 英国化学学会。
