假根羽藻外周天线色素分子间能量传递

Energy Transfer between Pigments in outer Antenna of Bryopsis corticulans

假根羽藻外周天线捕光色素蛋白复合物(L ight-harvesting Comp lex II,LHC II)在不同聚集态的情况下,它所包含色素分子间的能量传递是不同的。采用荧光发射光谱和激发光谱技术对不同聚集态(单体、三聚体和寡聚体)的LHC II进行研究,发现三聚体中色素分子间的能量传递效率比较高,单体要小一些。520 nm激发下,类胡萝卜素分子向叶绿素a分子的能量传递效率:三聚体约为64%、单体约为56%;650 nm激发下,叶绿素b分子向叶绿素a分子的能量传递效率:三聚体约为89%、单体约为78%。寡聚体的能量传递要复杂些,从光谱分析出它包含两种不同吸收光谱特性的叶绿素b分子,吸收峰分别为480 nm和468 nm,其中蓝区吸收峰为480 nm的叶绿素b分子向发射685 nm荧光的叶绿素a分子的能量传递效率要小于75%。

Fluorescence emission and excitation spectroscopy were used to detect the energy transfer between pigments in outer antenna （Light-harvesting Complex Ⅱ, LHC Ⅱ） subcomplexes, monomer, trimer and aggregate. The spectra showed that energy transfer efficiencies between pigments are high in trimer, lower in monomer. In the case of excitation 520 nm, the energy transfer efficiency from carotenoid molecule to chlorophyll a is about 64 % in trimer, and 56 % in monomer. In the case of excitation 650 nm, the energy transfer efficiency from chlorophyll b to chlorophyll a is about 89 % in trimer, and 78 % in monomer. The energy transfer in aggregate is complex. The analysis of spectra showed that aggregate contain two kinds of chlorophyll b. Their absorption peaks are 480 nm and 468 nm respectively. From chlorophyll b molecule absorbing at 480 nm to chlorophyll a molecule emitting at 685 nm, the energy transfer efficiency is less than 75 %.