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在模拟生理条件下,运用荧光光谱、激光闪光光解(LFP)和分子对接等技术研究了8种具有抗肿瘤活性的嘧啶衍生物(PDs,其中PDs A 5-FU为成药,PDs B-H为实验室自制)与人血清白蛋白(HSA)的相互作用.利用Stern-Volmer方程和激光闪光光解技术分析了PDs对HSA的荧光猝灭机制,PDs A和B为静态猝灭,PDs G和H为动态猝灭.用双倒数曲线法得出5种PDs与HSA的结合常数Ka和结合位点数n,在测定条件下5种PDs与载体结合位点数均为1,且均以弱结合力结合,通过热力学参数ΔH,ΔS和ΔG推测出PDs B,C和E与HSA之间的作用力为静电作用力和疏水作用力,PDs A和D与HSA之间的作用力是氢键和范德华力,分子对接结果与其一致.根据F9rster非辐射能量转移理论(FRET)分析了HSA和PDs之间的结合距离(r),其结果均小于4 nm,符合能量转移理论.进一步利用同步荧光、三维荧光和圆二色光谱考察了PDs与HSA结合过程中HSA空间构象的变化,结果显示,仅PDs A和C对HSA的芳香族氨基酸周围的疏水性略有增强作用.体外实验结果表明,HSA可以作为优良的载体来运输和储存PDs A~E,这为嘧啶衍生物的后续研究提供了可参考的实验数据.
Under simulated physiological conditions, eight kinds of antitumor pyrimidine derivatives (PDs), PDs A 5-FU as medicine and PDs BH as experiment, were studied by fluorescence spectroscopy, laser flash photolysis (LFP) and molecular docking Room self-made) and human serum albumin (HSA) .The fluorescence quenching mechanism of PDs on HSA was analyzed by Stern-Volmer equation and laser flash photolysis technique, the static quenching of PDs A and B, PDs G and H As dynamic quenching.The binding constants of five PDs and HSA were obtained by double reciprocal curve method.The binding sites of five PDs and vector were all 1 under the conditions of determination and all were bound by weak binding force , The thermodynamic parameters ΔH, ΔS and ΔG were deduced that the interaction between PDs B, C and E and HSA was electrostatic and hydrophobic. The forces between PDs A and D and HSA were hydrogen bond and van der Waals forces , And the molecular docking results are consistent with it.According to F9rster non-radiative energy transfer theory (FRET), the binding distance (r) between HSA and PDs was analyzed, the results were less than 4 nm, in line with the energy transfer theory.Further use of synchronous fluorescence, And circular dichroism spectroscopy to examine the spatial conformation of HSA during the binding of PDs to HSA The results showed that PDs A and C only slightly enhanced the hydrophobicity around the aromatic amino acids of HSA.Experimental results in vitro showed that HSA can be used as a good carrier to transport and store PDs A ~ E, which are pyrimidine derivatives The follow-up study provides experimental data for reference.