Phycobilisomes (PBs) absorb light and supply downstream photosynthetic processes with excitation energy in many cyanobacteria and algae. In response to a sudden increase in light intensity, excess excitation energy is photoprotectively dissipated in PBs by means of the orange carotenoid protein (OCP)-related mechanism or via a light-activated intrinsic decay channel. Recently, we have identified that both mechanisms are associated with far-red emission states. Here, we investigate the far-red states involved with the light-induced intrinsic mechanism by exploring the energy landscape and electro-optical properties of the pigments in PBs. While Stark spectroscopy showed that the far-red states in PBs exhibit a strong charge-transfer (CT) character at cryogenic temperatures, single molecule spectroscopy revealed that CT states should also be present at room temperature. Owing to the strong environmental sensitivity of CT states, the knowledge gained from this study may contribute to the design of a new generation of fluorescence markers.

中文翻译：

---

藻胆体中的电荷转移状态。

藻胆体 (PBs) 在许多蓝藻和藻类中吸收光并为下游光合作用过程提供激发能量。响应于光强度的突然增加，多余的激发能量通过橙色类胡萝卜素蛋白 (OCP) 相关机制或通过光激活的内在衰变通道在 PB 中以光保护方式消散。最近，我们发现这两种机制都与远红光发射状态有关。在这里，我们通过探索 PB 中颜料的能量景观和电光特性来研究与光诱导内在机制有关的远红态。虽然斯塔克光谱表明 PB 中的远红态在低温下表现出很强的电荷转移 (CT) 特征，单分子光谱显示，CT 状态也应该在室温下存在。由于 CT 状态对环境的强烈敏感性，从这项研究中获得的知识可能有助于设计新一代荧光标记。