PSⅡ核心复合物能量传递的飞秒时间分辨荧光光谱学研究

STUDY ON ENERGY TRANSFER IN CORE COMPLEX OF PSⅡ BY FEMTOSECOND FLUORESCENCE SPECTRA TECHNIQUE

运用稳态、瞬态荧光光谱技术对光系统Ⅱ核心复合物的能量传递动力学进行研究。分别用436 nm光脉冲激发叶绿素a分子、451 nm光激发叶绿素a和β-胡萝卜素分子、473和481 nm光激发β-胡萝卜素分子,得到5组反应能量传递、电荷重组等过程的寿命组分:8～40 ps为核心天线中β-胡萝卜素分子通过相邻β-胡萝卜素分子或中间叶绿素a向叶绿素a分子传递能量的时间;85～152 ps为核心天线色素分子激发能传递时间;201～925 ps反映部分电荷重组过程;1.031～1.21 ns为参与能量传递的色素分子从激发态衰退回到基态的时间;6.17～18.13 ns的长寿命时间组分归因于P680+Pheo-的重组过程。将荧光发射谱进行高斯解析,发现在核心复合物中还至少存在Chla683685、Chla680682、Chla673,677679三种特征叶绿素a分子。

Excitation energy transfer in the core complex of PSⅡ was studied by femtosecond fluorescence spectra technique, excited Chla molecules by 436 nm,Chla and β-car molecules by 451 nm pulse, while excited β-car molecules by 473 and 481 nm, five groups of time components were got. 8~40 ps components were the energy transfer time from β-car to Chla via other β-car or Chla molecules; 85~152 ps reflected the progress of energy capture by pigments of CP43 or Cp47, then transfer it to RC; 201~925 ps were the lifetime of partial charge recombination; 1.031~1.21 ns were contributed to the process of excited state decaying to ground state; 6.17~18.13 ns were related to radical pair state of P680+pheo-. Moreover, there were at least three characteristic Chla molecules in core complex: Chla_(683)^(682), Chla_(683)^(682)and Chla_(683)^(682).