摘要
在模拟人体生理条件下(pH 7.4),应用荧光、同步荧光、紫外吸收光谱法和圆二色谱法,研究了磺胺甲噻二唑(STZ)与人血清白蛋白(HSA)的相互作用。荧光猝灭实验结果表明,STZ对HSA内源荧光具有较强的猝灭能力,属于形成复合物的单一静态猝灭,氢键和范德华力是主要驱动力,结合常数Ka达到105 L·mol-1,表明STZ与HSA有较强的亲合力,STZ与HSA有一个结合位点,位于HSA的Site I。紫外吸收光谱、同步荧光光谱和圆二色谱分析表明,STZ与HSA结合诱导了HSA的二级结构发生了部分改变,导致蛋白质α-螺旋和β-转角含量增加,β-折叠和无规则卷曲含量减少。表面疏水性测定结果显示,STZ-HSA复合物的形成引起HSA表面疏水性增加。本研究为认识STZ与HSA的结合机制和药理作用提供重要信息。
The binding interaction between sulfamethizole（STZ）and human serum albumin（HSA）was investigated by fluorescence,synchronous fluorescence,UV-vis absorption and circular dichroism（CD）spectroscopy under simulative physiological conditions （pH 7.4）.The results of fluorescence titration revealed that STZ had a strong ability to quench the intrinsic fluorescence of HSA through a single static quenching process,and the interaction between STZ and HSA was mainly driven by hydrogen bonds and van der Waals forces.The binding constants Ka reached 105 L·mol^-1 ,and the number of binding sites was approximately equal to 1 .The site marker displacement experiments suggested the location of STZ binding to HSA was Sudlow’s site I in subdomain IIA.Analysis of UV-vis absorption,synchronous fluorescence and CD spectra demonstrated that the addition of STZ resulted in the conformational alteration of HSA with increase in the content of α-helix and β-turn,and decrease in β-sheet and random coil content.The determina-tion of protein surface hydrophobicity （PSH）indicated that STZ binding to HSA caused an increase in the PSH.This study could provide valuable information for understanding the binding mechanism of SZT with HSA and the pharmacological effect of STZ in biological processes.
出处
《南昌大学学报（理科版）》
CAS
北大核心
2014年第5期477-482,共6页
Journal of Nanchang University(Natural Science)
基金
国家自然科学基金项目(Nos.21167013
31460422)
高等学校博士点基金项目(20123601110005)
江西省自然科学基金项目(20143ACB20006
20142BAB204001)
江西省科技支撑项目(20141BBG70092)
食品科学与技术国家重点实验室基金项目(SKLF-ZZB-201305
SKLF-ZZA-201302)
关键词
磺胺甲噻二唑
人血清白蛋白
荧光猝灭
圆二色谱
sulfamethizole
human serum albumin
fluorescence quenching
circular dichroism spectroscopy
