【摘要】 采用飞秒时间分辨荧光光谱技术在室温下用波长为495nm的光激发,研究了假根羽藻LHCⅡ的同质三聚体和异质三聚体这两种不同聚集形式蛋白复合物的光谱特性和传能特性将实验获得的两样品的荧光光谱分别进行高斯解析,各得到5条亚谱带,并分析得出同质三聚体的四种特征Chl分子的光谱特性和异质三聚体的五种特征Chl分子光谱特性,另外还对两蛋白复合物的荧光光谱作了比较利用Global优化处理方法,建立多指数拟合联立方程对荧光衰减曲线进行拟合处理,得到同质三聚体Chl分子传能的寿命165±8.5fs、2.2±0.6ps、5.1±0.1ns;异质三聚体Chl分子传能的寿命255±6.3fs、4±0.8ps和3.8±0.1ns;并且将这些时间常数作出归属将其分析比较,快组分同质三聚体的传能速率较高,推断组成同质三聚体的同种脱辅基蛋白间的结合程度较组成异质三聚体的不同脱辅基蛋白间的更紧密,使其上结合的Chl分子空间位置更近,更有利于能量的迅速传递;而慢组分同质三聚体的偏大,可能是由于其经历的传能途径较长,传能机制上也和异质三聚体不同所致更多还原

【Abstract】 Femtosecond-time-resolved fluorescence spectroscopy technology has been carried out to study the fluorescence spectral properties and energy transfer properties in homotrimer and heterotrimer of the light-harvesting complex Ⅱprepared from Bryopsis corticulans , which is excitated at 495 nm and room temperature . Both homotrimer and heterotrimer have obtained five spectral components by Gauss analysis, and each of which reflects different spectral properties. Furthermore, the fluorescence spectra of the two complexes have been analyzed and compared. In addition, Triexponential time fitting for the fluorescence decay curve of homotrimer yields 3 components lifetimes of 165±8.5 fs, 2.2±0.6 ps and 5.1±0.1 ns, of hetermotrimer receives 3 components lifetimes of 255±6.3 fs, 4±0.8 ps and 3.8±0.1 ns, and all of which have been given ascription. Here, the two shorter time components of homotrimer are faster than those of heterotrimer.Which shows that the protein binding of homotrimer is more compact than that of heterotrimer, and causes the distances between the pigments of homotrimer can be shorter, and energy transfer between them be faster.更多还原