Tablet Cristina, Hillebrand Mihaela
Department of Physical Chemistry, University of Bucharest, Bd. Regina Elisabeta, 4-12, Bucharest, Romania.
Spectrochim Acta A Mol Biomol Spectrosc. 2008 Sep;70(4):740-8. doi: 10.1016/j.saa.2007.09.003. Epub 2007 Sep 18.
The 3-carboxy-5,6-benzocoumarinic acid (BzCum) presents important emission properties that could make it suitable to be used as a fluorescence marker for proteins. Since the guest-cyclodextrin interaction can be used as a model for the ligand-protein interaction, the host-guest complexes of BzCum with alpha-, beta-, gamma-, 2-hydroxypropyl-beta-cyclodextrin (2-HP-beta-CD) and 2-hydroxypropyl-gamma-cyclodextrin (2-HP-gamma-CD) were investigated by means of steady-state fluorescence measurements. As the guest may exist either in anionic or in neutral form, the experiments were performed at two different pH values, 9.48 and 2.11. The association constants and the stoichiometry of the complexes were estimated by non-linear regression analysis. A theoretical study of the complexes was made using molecular mechanics (MM) calculation methods. The electrostatic and van der Waals contributions to the energy were estimated and a discussion was made on this basis.
3-羧基-5,6-苯并香豆素酸（BzCum）具有重要的发射特性，这使其适合用作蛋白质的荧光标记物。由于客体-环糊精相互作用可作为配体-蛋白质相互作用的模型，因此通过稳态荧光测量研究了BzCum与α-、β-、γ-、2-羟丙基-β-环糊精（2-HP-β-CD）和2-羟丙基-γ-环糊精（2-HP-γ-CD）的主客体复合物。由于客体可能以阴离子或中性形式存在，实验在9.48和2.11两个不同的pH值下进行。通过非线性回归分析估计了复合物的缔合常数和化学计量比。使用分子力学（MM）计算方法对复合物进行了理论研究。估计了静电和范德华对能量的贡献，并在此基础上进行了讨论。
