摘要
采用荧光光谱滴定法研究了葫芦[7]脲(CB[7])与牛血清白蛋白(BSA)的相互作用。实验发现,在常见的pH 7.4时,BSA的荧光强度随着CB[7]浓度的增大而明显降低,猝灭常数随温度升高而逐渐减小。结果表明,CB[7]能与BSA相结合,形成较稳定的配合物,BSA内源荧光猝灭属静态猝灭机理。分别采用Stern-Volmer方程和Lineweaver-Burk双倒数方程处理实验数据,获得了不同温度下的反应结合常数、结合位点数以及相关热力学参数。在298K时,其表观结合常数(KA)为2.337×105 L.mol-1,结合位点数为1.078。基于热力学参数判定CB[7]与BSA之间存在协同的疏水作用和静电作用,这表明一方面BSA的氨基酸残基上的非极性基团可部分进入CB[7]疏水性的腔体,另一方面BSA又能与CB[7]端口质子化的羰基产生静电作用。同步荧光技术研究发现CB[7]没有引起BSA构象的变化,这为葫芦脲在药物载体和生命科学领域的应用提供有用的信息。
The interaction between cucurbit[7]uril（CB[7]） and bovine serum albumin（BSA） was first studied by fluorescence spectroscopy. In pH 7. 4 Tris buffers, the intrinsic fluorescence quenching of BSA dropped with the increase of the concentration of CB[7]. The quenching constant decreased with the rise of the temperature. As a result of the formation of CB[7]-BSA complex,the fluorescence quenching was static. The data related were analyzed according to the Stern-Volmer equation and the Lineweaver-Burk double- reciprocal equation. The binding constant, binding site number and the thermodynamic parameters were ob- tained at different temperatures. At 298 K, the apparent binding constant （KA） was 2. 337 ×105 L · mol^-1 , and the binding sites is 1. 078. Based on the thermodynamic parameter analysis, the hydrophobic and electrostatic interactions were the main force between CB[7]and BSA. On the one hand, the amino acid res- idues of BSA on the part of non-polar groups could enter the CB [7] hydrophobic cavity, On the other hand,BSA might be able to protonated carbonyl electrostatic interaction with CB [7] easily. Synchronous fluorescence indicated that CB [7] did not produce changes in the conformation of BSA,whieh could pro- vide useful information for the development and utilization of cucurbiturils in the field of biology and drug carriers.
出处
《南昌大学学报（理科版）》
CAS
北大核心
2012年第1期61-64,72,共5页
Journal of Nanchang University(Natural Science)
基金
江西省教育厅科技基金资助项目(GJJ11274)
关键词
荧光光谱法
脲
牛血清白蛋白
相互作用
fluorescence spectroscopy
cucurbit[7] uril
bovine serum albumin
iriieraction
