光系统Ⅱ核心天线的低温荧光光谱及动力学研究(英文)

Low-Temperature Fluorescence Spectroscopy and Kinetics in the Photosystem Ⅱ Core Complex

采用稳态及飞秒荧光光谱技术研究了光系统Ⅱ中核心复合物在83K、160K和273K低温下的能量传递途径.激发波长为507nm.随着温度的升高,稳态荧光光谱逐渐发生蓝移.通过对不同温度下稳态光谱进行高斯解析,获得5个特征叶绿素a分子,分别为Chla 670670.4,Chla680681.9,Chla683683.9,Chla687687.5687.8689和Chla690698.0,其中仅有Chla687687.5687.8.689在3个温度下的光谱中都解析获得,并且其谱宽以及荧光比例都随着温度升高而增加,因此推断温度对CP47中易裂解的叶绿素a分子有较大的影响.在680nm以及690nm波长处对不同温度下的时间曲线利用F900时间处理系统进行拟合,获得73ps、110ps、186ps、246～972ps和1～3.7ns5个时间组分。其中,73ps是电荷分离的时间;110ps和186ps是β-Car分子受激发后,将激发能最终传递给反应中心所需要的时间;246～972ps是电荷重组的时间过程;而1～3.7ns是激发态分子发生电荷重组后又衰退回到基态的时间.73ps的时间组分只在83K温度下得到,因此,随着温度降低,可以探测到快的时间组分.此外,对光谱随温度升高而发生蓝移进行了分析.

Low-temperature fluorescence spectroscopy and kinetics in the core complex of photosystem Ⅱ were studied with the methods of steady state and femtosecond fluorescence spectra techniques. The spectra at 83 K, 160 K and 273 K show the maximum becomes blueshifted from 693.0 nm at 83 K to 683.0 nm at 160 K, and it is almost no shift at above 160 K. And the shoulder at long wavelength region becomes less apparent as the temperature increasing. Five groups of Chlorophyll a molecules marked as Chl a670^670.4, Chl a680^681.9, Chl a683^683.9, Chl a687^687.5,687.8.689, Chl a690^698.0 were discovered from spectra at three temperatures, Based on the analyses of decay kinetics, five lifetime components were obtained to be 73 ps, 110ps, 186 ps, 246-972 psand 1-3.7 ns. With the decreasing of temperature, the faster time component can be detected. In addition, the blueshift of the spectrum was discussed.