光谱与停流荧光法研究肌红蛋白及其突变体D60K与表面活性剂的相互作用

Spectroscopy and Stopped-Flow/Fluorescence Studies on the Interactions of Myoglobin and Its Mutant(D60K) with Surfactants

用停流荧光法、紫外光谱法、荧光光谱法和圆二色(CD)光谱法研究了肌红蛋白(Mb)及其突变体Mb(D60K)分别与两种表面活性剂的相互作用.停流荧光数据表明不同浓度的十二烷基硫酸钠(SDS)和十六烷基三甲基溴化铵(CTAB)与Mb及Mb(D60K)相互作用均为(准)一级反应,虽然Mb(D60K)只是将肌红蛋白表面的60位天冬氨酸突变为赖氨酸,但二者性质差异显著,说明60位氨基酸对蛋白质性质影响较大.紫外、荧光与圆二色谱的结果也表明在上述表面活性剂作用下肌红蛋白及其突变体结构与功能均发生变化,其适应性和稳定性有一定差异.综合数据分析得知,肌红蛋白突变体D60K在表面活性剂溶液中性质更加稳定.

The interactions of myoglobin（Mb） and its mutant Mb（D60K） with two surfactants were studied using stopped-flow fluorescence spectroscopy,ultraviolet-visible（UV-Vis） absorption spectroscopy,fluorescence spectroscopy,and circular dichroism（CD） spectroscopy.The Mb external asparagine 60 into lysine,stopped-flow fluorescence results showed that the interactions of different concentrations of sodium dodecyl sulfate（SDS） and cetyltrimethyl ammonium bromide（CTAB） with Mb and Mb（D60K） were all quasi-first order reactions.Although Mb（D60K） was simply altered,the remarkable differences observed indicated that amino acid 60 influences the protein function greatly.Furthermore,results from UV-Vis spectroscopy,fluorescence spectroscopy and CD spectroscopy all indicated that the configurations and functions of Mb and Mb（D60K） were changed by the surfactants.The data indicates that Mb and its mutant exhibit different adaptabilities and stabilities in the surfactant solutions.From a comprehensive and comparative data analysis,we determined that the mutant D60K has more stable and adaptable functional and structural properties.