School of Molecular Sciences, Arizona State University , Tempe, Arizona 85287, United States.
Nano Lett. 2017 Feb 8;17(2):1174-1180. doi: 10.1021/acs.nanolett.6b04846. Epub 2017 Jan 19.
Taking inspiration from photosynthetic mechanisms in natural systems, we introduced a light-sensitive photo protective quenching element to an artificial light-harvesting antenna model to control the flow of energy as a function of light intensity excitation. The orange carotenoid protein (OCP) is a nonphotochemical quencher in cyanobacteria: under high-light conditions, the protein undergoes a spectral shift, and by binding to the phycobilisome, it absorbs excess light and dissipates it as heat. By the use of DNA as a scaffold, an antenna system made of organic dyes (Cy3 and Cy5) was constructed, and OCP was assembled on it as a modulated quenching element. By controlling the illumination intensity, it is possible to switch the direction of excitation energy transfer from the donor Cy3 to either of two acceptors. Under low-light conditions, energy is transferred from Cy3 to Cy5, and under intense illumination, energy is partially transferred to OCP as well. These results demonstrate the feasibility of controlling the pathway of energy transfer using light intensity in an engineered light-harvesting system.
受自然系统光合作用机制的启发，我们在人工光捕获天线模型中引入了光敏感光保护猝灭元件，以根据光强激发来控制能量流。橙色类胡萝卜素蛋白（OCP）是蓝细菌中的非光化学猝灭剂：在高光条件下，该蛋白会发生光谱位移，并通过与藻胆体结合来吸收多余的光并将其作为热量耗散。通过使用 DNA 作为支架，构建了由有机染料（Cy3 和 Cy5）组成的天线系统，并将 OCP 组装在其上作为调制猝灭元件。通过控制照明强度，可以将激发能量从供体 Cy3 转移到两个受体之一的方向进行切换。在低光照条件下，能量从 Cy3 转移到 Cy5，而在强烈光照下，能量也会部分转移到 OCP。这些结果表明，在工程化的光捕获系统中，使用光强来控制能量转移途径是可行的。
