高等植物光系统Ⅱ大量捕光天线与量子点之间的定向连接及共振能量传递

Site-Selective Chelation and Excitation Energy Transfer between the Higher Plant Major Light-Harvesting Complexes and Quantum Dots

高等植物光系统Ⅱ大量捕光天线(light-harvesting complexes of photosystem Ⅱ,LHCⅡ)能与有机或无机材料连接,构建仿生的捕捉光能的新型材料。将量子点(quantum dot,QD)与LHCⅡ定向连接,构建共振能量传递体系,得到一系列不同摩尔比的QD-LHCⅡ杂合复合物(QD与LHCⅡ的摩尔比分别为1∶64、1∶32、1∶16、1∶12、1∶8、1∶4、1∶2.7、1∶2和1∶1.6)。光谱结果显示,随着摩尔比的增大,越来越多QD的激发能传递给LHCⅡ,并在1∶2.7时达到饱和。而无组氨酸标签的天然LHCⅡ与QD共孵育后,LHCⅡ和QD的荧光发射并没有显著变化。以上结果说明,本研究实现了定向连接后QD到LHCⅡ的显著共振能量传递,而定向连接对于这种共振能量传递是必要条件。

The major light-harvesting complexes of photosystem II （LHCII） have been linked to many organic or inorganic materials to construct bio-inspired new hybrid materials. In this study, the authors reported a hybrid complex of recombinant LHCII and water-soluble quantum dots （QD） linked by nickel-nitriloacetic acid （NTA.Ni） with a series of molar ratio between LHCII and QD （1：64, 1：32, 1 ： 16, 1 ： 12, 1：8, 1：4, 1 ： 2.7, 1 ： 2, 1 ： 1.6） on the QD and histidine tag on the LHCII. The spectroscopic results showed that the fluorescence at 680 nm from LHCII increased when more QD molecules were put into the hybrid system. The enhancement reached the maximum and saturated when the molar ratio between LHCII and QD was 2.7 ： 1. The fluorescence spectra results could be explained by resonance energy transfer mechanism from QD to LHCII. Moreover, no obvious energy transfer was observed between native LHCII and QD mixture and this highlighted the necessity of linkage for such energy transfer.