Light-Harvesting Complex II in Controlled Architectures: Visualizing Changes in Fluorescence Lifetimes
Light-Harvesting Complex II in Controlled Architectures: Visualizing Changes in Fluorescence Lifetimes
复制标题
受控架构中的光捕获复合物 II：可视化荧光寿命的变化
DOI：
10.1016/j.bpj.2016.11.2356
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发表时间：
2017
影响因子：
3.4
通讯作者：
Adams P
中科院分区：
文献类型：
--
作者：
Adams P
在光合作用的第一阶段，捕光膜蛋白复合体形成一个相互连接的网络，以电子激发态的形式高效地吸收光子并传递能量。捕光复合体II(LHCII)具有多种重要作用，包括：(1)作为光系统II(PSII)的天线复合体；(2)激活非光化学猝灭(NPQ)；(3)促进类囊体膜的多层堆积。在这项研究中，我们研究了LHCII的光学性质如何依赖于蛋白质-蛋白质和脂-蛋白质相互作用。在固体衬底上制备了单层或多层LHCII的微尺度阵列图案，并用原子力显微镜和荧光显微镜结合光谱和寿命成像进行了研究。荧光光谱证实，LHCII的天然发色团结构保持不变。有趣的是，LHCII在多层膜中具有较低的荧光寿命，这表明LHCII-LHCII相互作用的增加促进了猝灭态的形成。在其他实验中，LHCII以不同的蛋白质密度沉积在固体载体上，并在周围有或没有脂膜的情况下进行。当加入脂类时，LHCII的荧光被强烈增强，这可能是由于脂类有效地稀释了LHCII膜的浓度，减少了LHCII-LHCII的相互作用，从而减少了自猝灭。这些实验揭示了根据LHCII-LHCII和LHCII-脂质相互作用在猝灭和非猝灭状态之间的转换。
In the first stages of photosynthesis, light-harvesting membrane protein complexes form an interconnected network, absorbing photons and transferring energy as electronic excited states with high efficiency. Light Harvesting Complex II (LHCII) has several important roles, including:(i) acting as an antenna complex for Photosystem II (PSII),(ii) activating Non-Photochemical Quenching (NPQ) and (iii) promoting multi-layer stacking of thylakoid membranes. In this study, we investigated how the optical properties of LHCII depend upon protein-protein and lipid-protein interactions. Microscale array patterns of either single-or multi-layers of LHCII were generated on solid substrates, and studied by atomic force microscopy and fluorescence microscopy with spectral and lifetime imaging. Fluorescence spectra confirmed that the native chromophore organization of LHCII was maintained. Interestingly, LHCII had lower fluorescence lifetimes in multi-layers, suggesting that increased LHCII-LHCII interactions promote the quenched state. In other experiments, LHCII was deposited onto solid supports at varying protein density and in the presence or absence of a surrounding lipid membrane. LHCII fluorescence was strongly enhanced when lipids were added, potentially due to decreased self-quenching as the lipids effectively dilute the LHCII membrane concentration, decreasing LHCII-LHCII interactions. These experiments reveal switching between quenched and unquenched states depending on LHCII-LHCII and LHCII-lipid interactions.