Zhu Jingfeng, Li Daojin, Jin Jing, Wu Longmin
State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou, Gansu 730000, China.
Spectrochim Acta A Mol Biomol Spectrosc. 2007 Oct;68(2):354-9. doi: 10.1016/j.saa.2006.11.045. Epub 2006 Dec 8.
Binding of farrerol to lysozyme (LYSO) was investigated at 302, 313 and 318 K at pH 7.4 using spectrophotometric techniques such as fluorescence emission, circular dichroism (CD) and UV absorption. The data obtained from fluorescence quenching experiments showed that farrerol was bound to LYSO and the affinity was enhanced by the addition of farrerol. When the concentration ratio of farrerol to LYSO was higher than 5.4, both the binding constant and the binding stoichiometry went up. Based on the thermodynamic parameters evaluated from the van't Hoff equation, the enthalpy change (deltaH degrees ) and entropy change (deltaS degrees ) were derived to be negative values. They indicated that both van der Waals forces and hydrogen bonds are the major interactions between farrerol and LYSO. A value of 2.67 nm for the average distance r between farrerol (acceptor) and tryptophan residues (Trp) of LYSO (donor) was derived from the fluorescence resonance energy transfer. Besides, the change in the conformation of LYSO was observed, being caused by the interaction with farrerol.
在302、313和318K温度、pH 7.4条件下，采用荧光发射、圆二色性（CD）和紫外吸收等分光光度技术研究了杜鹃素与溶菌酶（LYSO）的结合情况。荧光猝灭实验所得数据表明，杜鹃素与溶菌酶发生了结合，且添加杜鹃素后亲和力增强。当杜鹃素与溶菌酶的浓度比高于5.4时，结合常数和结合化学计量数均升高。根据由范特霍夫方程评估得到的热力学参数，推导出焓变（ΔH°）和熵变（ΔS°）均为负值。这表明范德华力和氢键都是杜鹃素与溶菌酶之间的主要相互作用。通过荧光共振能量转移得出，杜鹃素（受体）与溶菌酶（供体）色氨酸残基（Trp）之间的平均距离r为2.67nm。此外，观察到溶菌酶的构象发生了变化，这是由与杜鹃素的相互作用引起的。
