Successive energy transfer within multiple photosensitizers assembled in a hexameric hemoprotein scaffold
Successive energy transfer within multiple photosensitizers assembled in a hexameric hemoprotein scaffold
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DOI：
10.1039/c7cp05257j
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发表时间：
2018-02-07
影响因子：
3.3
通讯作者：
Hayashi, Takashi
中科院分区：
文献类型：
--
作者：
Mashima, Tsuyoshi;Oohora, Koji;Hayashi, Takashi
通过开发六聚血红蛋白（HTHP）支架，证明了多个光敏剂的组装，作为光收集模型，以复制自然系统光敏剂组件内发生的连续能量转移。在我们的模型中，6个锌原卟啉IX （ZnPP）分子通过超分子相互作用排列在HTHP的血红素结合位点，5个荧光素（Flu）分子和1个德克萨斯红（Tex）分子分别作为供体和受体光敏剂以共价键连接在HTHP蛋白表面。从光激发的Flu到Tex的激发态能量的流动通过两条途径发生：从Flu到Tex的直接能量转移（途径1）和通过ZnPP的能量转移（途径2）。稳态和时间分辨荧光测量显示，这些途径（路径1：路径2）的能量传递比是39:61。这些发现表明，来自5个Flu分子和6个ZnPP分子的激发能量被收集在一个Tex分子上，作为一个漏斗状的底部进行光收集。目前使用六聚体血红蛋白支架的系统是构建具有多个光敏剂的人工光收集系统的有希望的候选者，以促进太阳能的有效利用。
An assembly of multiple photosensitizers is demonstrated by development of a hexameric hemoprotein (HTHP) scaffold as a light harvesting model to replicate the successive energy transfer occuring within photosensitizer assemblies of natural systems. In our model, six zinc protoporphyrin IX (ZnPP) molecules are arrayed at the heme binding site of HTHP by supramolecular interactions and five fluorescein (Flu) molecules and one Texas Red (Tex) molecule as donor and acceptor photosensitizers, respectively, are attached to the HTHP protein surface with covalent linkages. The flow of excited energy from photoexcited Flu to Tex occurs via two pathways: direct energy transfer from Flu to Tex (path 1) and energy transfer via ZnPP (path 2). Steady state and time- resolved fluorescence measurements reveal that the energy transfer ratio of these pathways (path 1 : path 2) is 39 : 61. These findings indicate that the excited energy originating at five Flu and six ZnPP molecules is collected at one Tex molecule as a funnel-like bottom for light harvesting. The present system using the hexameric hemoprotein scaffold is a promising candidate for construction of an artificial light harvesting system having multiple photosensitizers to promote efficient use of solar energy.