Research Center for Food Safety and Nutrition, Key Lab of Urban Agriculture (South), Bor S. Luh Food Safety Research Center, School of Agriculture & Biology, Shanghai Jiao Tong University, Shanghai 200240, China.
Research Center for Food Safety and Nutrition, Key Lab of Urban Agriculture (South), Bor S. Luh Food Safety Research Center, School of Agriculture & Biology, Shanghai Jiao Tong University, Shanghai 200240, China.
Spectrochim Acta A Mol Biomol Spectrosc. 2018 Nov 5;204:708-716. doi: 10.1016/j.saa.2018.06.103. Epub 2018 Jun 28.
In this study, we report the glycation mediated effect of bovine serum albumin (BSA) on the molecular interaction mechanism of cyanidin-3-O-glucoside (C3G) by molecular modelling, Uv-visible spectroscopy, transmission electron microscopy (TEM), fluorescence spectroscopy, and circular dichroism spectroscopy studies. The structures of advanced glycation end-products (AGEs) modified BSA were modelled, energy minimized and analyzed for binding affinity by molecular docking studies using Autodock Vina. Glycation experiments are carried out using glucose and methylglyoxal to validate the molecular modelling results on the interaction of modified BSA with C3G. The modified structures were characterized by reduction in the binding pocket volume, surface, depth, hydrophobicity, and hydrogen bond donors/acceptors. Arg-194, Arg-196, Arg-198, Arg-217, Arg-409, Lys-114, Lys-116, Lys-204, Lys 221, and Lys-439 were found to be crucial in the context of glycation of BSA. TEM images represented the formation of unique globular aggregates in the event of glycation. Uv-visible spectroscopic studies showed the formation of new chromophores between 300 and 400 nm in the event of glycation. Fluorescence quenching was observed in a differential manner in the presence of C3G on glycation modified BSA. Circular dichroism studies suggested the loss of helical structure and formation of β-sheeted structure upon glycation, but subsequent C3G binding has resulted in the increase towards helical structure. Our findings suggested that drug binding affinity has been certainly impaired due to glycation and subsequent AGE modification. Arg-p modification has more austere impact on the structure and would affect the binding properties. We conclude that C3G had differential modulation of binding properties on glycated BSA which can help to protect the stability and bioavailability that has been impaired due to glycation mediated structural changes.
在这项研究中，我们通过分子建模、紫外可见光谱、透射电子显微镜（TEM）、荧光光谱和圆二色光谱研究，报告了牛血清白蛋白（BSA）的糖化介导作用对矢车菊素-3-O-葡萄糖苷（C3G）分子相互作用机制的影响。通过 Autodock Vina 使用分子对接研究对修饰的 BSA 的高级糖基化终产物（AGEs）结构进行建模、能量最小化和结合亲和力分析。使用葡萄糖和甲基乙二醛进行糖化实验，以验证分子建模结果在修饰的 BSA 与 C3G 相互作用中的作用。修饰的结构通过减少结合口袋的体积、表面积、深度、疏水性和氢键供体/受体来表征。Arg-194、Arg-196、Arg-198、Arg-217、Arg-409、Lys-114、Lys-116、Lys-204、Lys221 和 Lys-439 被发现是 BSA 糖化过程中的关键。TEM 图像代表了糖化过程中独特的球状聚集体的形成。紫外可见光谱研究表明，糖化过程中在 300 至 400nm 之间形成了新的生色团。在存在 C3G 的情况下，荧光猝灭以不同的方式观察到修饰的 BSA 的糖化。圆二色光谱研究表明，糖化后螺旋结构丢失并形成β-折叠结构，但随后 C3G 结合导致螺旋结构增加。我们的研究结果表明，由于糖化和随后的 AGE 修饰，药物结合亲和力肯定受到了损害。Arg-p 修饰对结构的影响更为严厉，会影响结合特性。我们得出结论，C3G 对糖化 BSA 的结合特性具有不同的调节作用，这有助于保护由于糖化介导的结构变化而受损的稳定性和生物利用度。
