“on/Off” Switchable Sequential Light-Harvesting Systems Based on Controllable Protein Nanosheets for Regulation of Photocatalysis

A controllable protein nanostructures-based "On/Off" switchable artificial light-harvesting system (LHS) with sequential multistep energy transfer and photocatalysis was reported herein for mimicking the natural LHS in both structure and function. Single-layered protein nanosheets were first constructed via a reversible covalent self-assembly strategy using cricoid stable protein one (SP1) as building blocks to realize an ordered arrangement of pigments. Fluorescent chromophores like carbon dots (CDs) can be precisely distributed on the protein nanosheets superficially via electrostatic interactions and make the ratio between donors and acceptors adjustable. After being anchored with a photocatalysis center (eosin-5-isothiocyanate, EY), the constructed LHS could sequentially transfer energy between two kinds of chromophores (CD1 and CD2), and further transfer to EY center with a high efficiency of 84%. Interestingly, the Förster resonance energy transfer (FRET) process of our LHS could be reversibly "On/Off" switched by the redox regulated assembly and disassembly of SP1 building blocks. Moreover, the LHS has been further proved to promote the yield of a model cross-coupling hydrogen evolution reaction and regulate the process of the reaction with the FRET process "On/Off" state.

本文报道了一种基于可控蛋白质纳米结构的“开/关”可切换人工光采集系统（LHS），具有顺序多步能量转移和光催化作用，用于在结构和功能上模仿天然 LHS。首先使用环状稳定蛋白一 (SP1) 作为构建块，通过可逆共价自组装策略构建单层蛋白质纳米片，以实现颜料的有序排列。碳点（CD）等荧光发色团可以通过静电相互作用精确分布在蛋白质纳米片表面，并使供体和受体之间的比例可调。构建的LHS锚定光催化中心（eosin-5-isothiocyanate，EY）后，可以在两种生色团（CD1和CD2）之间顺序转移能量，并进一步转移到EY中心，效率高达84%。有趣的是，我们的 LHS 的福斯特共振能量转移 (FRET) 过程可以通过 SP1 构建块的氧化还原调节组装和拆卸来可逆地“开/关”切换。此外，LHS还被进一步证明可以提高模型交叉偶联析氢反应的产率，并通过FRET过程“On/Off”状态调节反应过程。