EMND与人血清白蛋白的分子作用机制

微波条件下,运用一锅法合成了二氢嘧啶-2-酮的衍生物—5-乙酯基-6-甲基-4-(4-硝基苯基)-3,4-二氢嘧啶-2-酮(EMND).运用同步荧光光谱、位点竞争结合实验、荧光共振能量转移(FRET)理论以及分子模拟技术研究了EMND与人血清白蛋白(HSA)的分子作用机制.实验结果表明:EMND与HSA的结合位点位于色氨酸(Trp214)附近,EMND的结合位点位于HSA的IIA亚域.通过FRET理论计算得出EMND与色氨酸残基的结合距离r=4.25nm,说明EMND与HSA之间能够发生非辐射能量转移.分子模拟表明EMND结合到HSA IIA亚域的疏水空腔,它们之间存在氢键作用,进一步印证了同步荧光及位点竞争结合实验结果.本研究对于在分子水平上理解小分子与生物大分子的相互作用本质以及设计基于二氢嘧啶-2-酮的药物等都有一定的参考作用.

Exploring the Molecular Interaction Mechanism of EMND with Human Serum Albumin

A dihydropyrimidinones derivative 5-(ethoxycarbonyl)-6-methyl-4-(4-nitrophenyl)-3,4-dihydropyrimidin-2(1H)-one(EMND)was synthesized by one pot method in this paper,under microwave assist.The molecular interaction mechanism of EMND with human serum albumin(HSA)was investigated by using synchronous fluorescence spectrum,site marker competitive binding assay,fluorescence resonance energy transfer(FRET)theory and molecular modeling technique.The study of synchronous fluorescence spectrum shows that the binding site of EMND on HSA is close to tryptophan residue(Trp214).Warfarin is a typical drug that binds to site I of HSA.To identify the binding site of EMND on the region of HSA,the site marker competitive binding experiments is employed by using warfarin that specifically binds to a known site on HSA.The information about EMND binding site on HSA can be obtained by monitoring the changes in the fluorescence of EMND bound HSA that are brought about by site I marker(warfarin).The site marker competitive binding experiment reveals that the binding site of EMND is located at site I(subdomain IIA)of HSA.At the same time,the binding distance between EMND and Trp residue is evaluated as r=4.25 nm with FRET theory,indicating that non-radiation energy transfer can occur between EMND and HSA with high probability.The molecular modeling investigations suggest that EMND binds to the hydrophobic cavity in subdomainⅡ A of HSA,and the hydrogen bonding plays an important role in stabilizing the formation of complex,which further confirms the results of synchronous fluorescence spectrum and site marker competitive binding assay.The synthesis and binding properties of the dihydropyrimidinone derivative reported herein expect to be helpful for understanding the interaction of small molecules with proteins at the molecular level and be useful for the design of new dihydropyrimidinone-based drugs.