Study of the interaction between sodium salts of (2
<i>E</i>
)‐3‐(4'‐halophenyl)prop‐2‐enoyl sulfachloropyrazine and bovine serum albumin by fluorescence spectroscopy
作者:Xuan Luo、Chuanrong Du、Jinrui Wei、Jiang Deng、Yijie Lin、Cuiwu Lin
DOI:10.1002/bio.2364
日期:2013.3
Three sodium salts of (2E)-3-(4'-halophenyl)prop-2-enoyl sulfachloropyrazine (CCSCP) were synthesized and their structures were determined by 1H and 13C NMR, LC-MS and IR. The binding properties between CCSCPs and bovine serum albumin (BSA) were studied using fluorescence spectroscopy in combination with UV–vis absorbance spectroscopy. The results indicate that the fluorescence quenching mechanisms between BSA and CCSCPs were static quenching at low concentrations of CCSCPs or combined quenching (static and dynamic) at higher CCSCP concentrations of 298, 303 and 308 K. The binding constants, binding sites and corresponding thermodynamic parameters (ΔH, ΔS, ΔG) were calculated at different temperatures. All ΔG values were negative, which revealed that the binding processes were spontaneous. Although all CCSCPs had negative ΔH and positive ΔS, the contributions of ΔH and ΔS to ΔG values were different. When the 4'-substituent was fluorine or chlorine, van der Waals interactions and hydrogen bonds were the main interaction forces. However, when the halogen was bromine, ionic interaction and proton transfer controlled the overall energetics. The binding distances between CCSCPs and BSA were determined using the Förster non-radiation energy transfer theory and the effects of CCSCPs on the conformation of BSA were analyzed by synchronous fluorescence spectroscopy. Copyright © 2012 John Wiley & Sons, Ltd.
合成得到(2E)-3-(4'-卤代苯基)丙-2-烯酰磺胺氯吡嗪的三种钠盐(CCSCP),通过1H、13C NMR,LC-MS和IR确定了其结构。利用荧光及紫外-可见吸收光谱研究了CCSCP与牛血清白蛋白(BSA)之 间的相互作用。结果表明,在298,303和308 K下,当低浓度CCSCP时,BSA与CCSCP之间的荧光猝灭为静态猝灭;当高浓度CCSCP时,则为静、动力学兼有猝灭方式。计算得到了不同温度下的结合平衡常数、结合位点和相应的 热力学参数(ΔH,ΔS,ΔG)。所有ΔG值均为负值,表明CCSCP与BSA的结合是自发的。所有CCSCP体系下,ΔH均为负值,而ΔS均为正值,但其对ΔG值的贡献不同。当4'取代基为氟或氯时,范德华力和氢键为主要作用力;而当卤素为溴时,离子相互作用和质子转移决定了体系的热力学性质。利用Förster非辐射能量转移理论计算了CCSCP与BSA之间的结合距离,通过同步荧光技术分析了CCSCP对BSA构象的影响。 © 2012 John Wiley & Sons, Ltd.