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为了探究肌红蛋白表面60位的Asp突变为Lys后对蛋白荧光强度的影响,在模拟生理条件下,利用荧光法和圆二色法对WT Mb及D60K Mb的结构及荧光光谱特性进行了对照研究,结果表明D60K Mb的荧光量子产率远大于WT Mb。通过研究pH值和结构对荧光量子产率的影响,发现Mb 60位天冬氨酸(Asp)突变为赖氨酸(Lys)后,蛋白表面电荷发生改变,导致蛋白的荧光量子产率明显增强;同时使蛋白内部的芳香族氨基酸较原来更暴露,极性增强,激发态分子的去激发过程由原来的无辐射能量转移为主转变为辐射能量转移为主,最终导致荧光强度增强。
In order to explore the effect of mutated Asp at position 60 of Myoglobin on the fluorescence intensity of protein, the structure and fluorescence spectra of WT Mb and D60K Mb were compared by fluorescence and circular dichroism under simulated physiological conditions The results showed that the fluorescence quantum yield of D60K Mb was much larger than WT Mb. By studying the effect of pH value and structure on the fluorescence quantum yield, it was found that the change of Mb60 Asp to Lys resulted in a change in the surface charge of the protein, resulting in a marked increase in the fluorescence quantum yield of the protein ; At the same time, the aromatic amino acids inside the protein are more exposed than the original ones, and the polarities are enhanced. The de-excitation process of the excited state molecules changes from the original non-radiative energy transfer to the radiative energy transfer, which finally leads to the enhancement of the fluorescence intensity.