分子模拟技术与光谱法结合研究抑菌剂磺胺二甲嘧啶与人血清白蛋白之间的相互作用

Molecular Modeling and Multi-spectroscopic Approaches to Study Interaction Between Antimicrobial Drug Sulfamethazine and Human Serum Albumin

目的:研究了磺胺二甲嘧啶(SMZ)与人血清白蛋白(HSA)之间的相互作用。方法:在模拟生理条件下,采用分子模拟技术、荧光猝灭光谱、三维荧光光谱及紫外-可见吸收光谱法研究SMZ与HSA之间的猝灭类型,计算二者之间的结合常数、结合位点数等。结果:分子模拟技术试验结果说明SMZ与HSA之间的相互作用主要是氢键和疏水作用;荧光猝灭试验结果表明SMZ可以使HSA发生荧光猝灭。在293,298,303,308 K的温度下,根据Scatchard方程计算结果可知SMZ与HSA间的结合常数分别为3.42×104,3.13×104,2.63×104,2.13×104mol·L-1,这说明SMZ和HSA之间的猝灭机制为静态猝灭,它们之间相应的结合位点数分别为0.99,0.96,0.98,1.09;在SMZ与HSA相互作用的体系中,它们之间的热力学常数:焓变和熵变的值分别为-18.76,22.80 kJ·mol-1,这说明结合过程可能同时存在静电作用和疏水作用;此外,通过三维荧光光谱和紫外-可见吸收光谱得到的数据可知:SMZ的加入会引起HSA二级结构的变化。结论:分子模拟技术与光谱法结合适合于研究SMZ与HSA之间的相互作用,具有简单快速,灵敏度高等优点。

Objective：To study the interaction of sulfamethazine （SMZ） with human serum albumin （HSA）.Method：The quenching mechanism,binding constants and binding sites （n） were studied using molecular modeling,fluorescence quenching spectroscopy,three-dimensional fluorescence spectroscopy and UV-vis absorption spectroscopy under simulative physiological conditions.Result：The experiment results obtained from molecular modeling indicated that there were hydrogen bonds and hydrophobic interactions between SMX and HSA; the fluorescence quenching spectra data showed that the fluorescence intensity of HSA was quenched by the gradual addition of SMX.The binding constants of SMX with HSA at 293,298,303,308 K were calculated to be 3.42 × 104,3.13 × 104,2.63 × 104,2.13 × 104 mol ·L-1,respectively,which means that the quenching mechanism was suggested as a static quenching.Meanwhile,corresponding numbers of binding sites （n） were calculated to be 0.99,0.96,0.98,1.09,respectively.The thermodynamic parameters of the reaction,namely standard enthalpy ΔH0 and entropy ΔS0,had been calculated to be-18.76 kJ ·mol-1 and 22.80 kJ ·mol-1,respectively,which suggested that the electrostatic and hydrophobic interactions were the predominant intermolecular forces in stabilizing the SMZ-HSA complex.Experimental results obtained from the three-dimensional fluorescence spectroscopy and UV-vis absorption spectroscopy confirmed that the secondary structure of HSA was altered in the presence of SMZ in aqueous solution.Conclusion：Molecular modeling and multi-spectroscopic approaches are good methods for investigating the interaction between SMZ and HSA.They have the advantages of high speed and high sensitivity.