稀土金属离子及pH诱导牛血清白蛋白构象变化的同步荧光光谱研究

用同步荧光法并辅以普通荧光法对不同浓度稀土离子及pH诱导的牛血清白蛋白(BSA)构象变化进行了详细研究, 发现稀土离子使色氨酸(Trp)残基的荧光蓝移, 荧光强度降低; 酪氨酸(Tyr)残基荧光峰位置不变, 稀土离子浓度较低时, 荧光峰强度降低, 而当浓度较高时, Tyr残基荧光峰强度反而增强. 据此推断了稀土离子与BSA结合反应中Trp残基微环境和Tyr残基微环境及构象的变化并与pH引起的变化进行了比较.

Synchronous Fluorescence Spectral Studies on Conformational Change of BSA Induced by Rare Earth Ions and pH

The conformational change of BSA induced by rare earth ions and pH were studied by synchronous fluorescence spectroscopy firstly. The results show that the synchronous fluorescence spectra of Trp have blue shift and are quenched in the presence of rare earth ions. While without obvious shift to Tyr, the fluorescence intensity of Tyr decreases when the concentration of rare earth ions is lower. However it increases when the rare earth ions concentration becomes higher. At last, the change of Trp, Tyr microenvironment and BSA conformation is induced by rare earth ions and pH is deduced. The functional difference between rare earth ions and pH was discussed.