用傅里叶变换红外光谱研究增强UV-B辐射对PSⅡ蛋白结构的影响

Effects of Ultraviolet-B Radiation on Protein Structure in PS Ⅱ Using Fourier Transform Infrared Spectroscopy

运用傅里叶变换红外光谱技术研究了增强紫外线-B(UV-B)辐射对植物光系统Ⅱ(PSⅡ)中膜蛋白结构的影响。结果显示在增强的UV-B辐射条件下,PSⅡ中蛋白的α-螺旋、β-折叠强度增加,而β-转角的强度下降了近一倍,并且这些结构与周围的耦合减弱。此外,UV-B辐射使酪氨酸残基苯酚环的结构发生改变,并使其微极性降低。UV-B辐射所诱导的以上结构的变化必然引起锰簇及色素和蛋白质之间的天然结合状态的改变,并导致光能传递、转换、电子传递以及放氧等一系列的变化。

The effects of ultraviolet-B（UV-B） radiation on protein structure in photosystem Ⅱ（PSⅡ） was studied using Fourier transform infrared spectroscopy.The results demonstrated that irradiation of the plant with enhanced UV-B caused the change in the structures of protein in PSII.The intensity of α-helix,β-sheet was increased,while the intensity of β-turn was decreased.The coupling of those structures with surrounding became weaker with UV-B radiation.Otherwise,the UV-B influenced the structure of tyrosine residue and made the polarity of tyrosine decrease.The changes caused by UV-B radiation could alter the combination between Mn cluster and pigments with protein inevitably.It would lead to a series of changes,such as the process of light transmission and conversion,electron transfer and oxygen evolution.