从核心天线到反应中心分子传能研究

Study on Molecule Energy Transfer from Core Antenna to Reaction Center

利用飞秒时间分辨光谱技术研究了PSⅡ核心复合物内 β Car分子和Chla分子传递光能到反应中心的时间特性 实验测得 ,在CP4 7中的β Car分子用了 15 0ps ,Chla分子用了 15ps ;在CP4 3中β Car分子用了 16 0ps ,Chla分子用了 2 0ps 利用超快光谱动力学实验曲线 ,理论计算出在核心天线中 β Car分子到Chla 6 6 2之间的能量传递速率为 1.18× 10 12 s- 1,β Car分子到相邻 β Car分子之间按速率 1.14× 10 12 s- 1传递能量 理论研究得出 ,在核心天线中 β Car分子接收到光能 ,以Dexter电子交换机制和F rster共振传能机制进行激发能传递 ,最后由Chla分子把能量传递到反应中心 ,在CP4 7中用了 139ps ,在CP4 3中用了 15 2ps 理论研究表明 ,在核心天线中 ,Chla分子接收到光能之后 ,以随机转移方式将能量迅速传递到反应中心P6 80 ,在CP4 7中用了 16 .8ps ,在CP4 3中用了 18ps 理论研究与实验研究基本符合.

Femtosecond time-resolved spectrum techniques have been used to study the time characteristic of energy transfer from Chla and β-Car molecule of the core antenna to the reaction center in the photosystem Ⅱ.By experiment Chla molecules of CP47 use 15 ps, β-Car molecules of CP47 use 150 ps, Chla molecules of CP43 use 20 ps, β-Car molecules of CP43 use 160 ps. Theory investigation has shown that 15 ps and 20ps are the energy transfer time on random transfer between neighboring Chla molecules in CP47 and CP43 respectively, 150 ps and 160 ps are the energy transfer time on a one-step Dexter electron exchange, Frster transfer, exciton transfer between neighboring β-Car and Chla molecules from the excited β-Car in the CP47 and CP43 to the reaction center. Theoretical calculation also has yielded an energy transfer rate 1.18×10 12s -1 from β-Car molecule to Chla662 and an energy transfer rate 1.14×10 12s -1 from β-Car molecule to neighboring β-Car mocecule in the core antenna.Theoretical calculation is in agreement with the experiment results basically.