Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands.
Biological Research Centre, Szeged, Temesvári krt. 62, Szeged, 6726, Hungary.
Photosynth Res. 2020 May;144(2):261-272. doi: 10.1007/s11120-020-00723-0. Epub 2020 Feb 19.
The phycobilisome (PBS) serves as the major light-harvesting system, funnelling excitation energy to both photosystems (PS) in cyanobacteria and red algae. The picosecond kinetics involving the excitation energy transfer has been studied within the isolated systems and intact filaments of the cyanobacterium Anabaena variabilis PCC 7120. A target model is proposed which resolves the dynamics of the different chromophore groups. The energy transfer rate of 8.5 ± 1.0/ns from the rod to the core is the rate-limiting step, both in vivo and in vitro. The PBS-PSI-PSII supercomplex reveals efficient excitation energy migration from the low-energy allophycocyanin, which is the terminal emitter, in the PBS core to the chlorophyll a in the photosystems. The terminal emitter of the phycobilisome transfers energy to both PSI and PSII with a rate of 50 ± 10/ns, equally distributing the solar energy to both photosystems. Finally, the excitation energy is trapped by charge separation in the photosystems with trapping rates estimated to be 56 ± 6/ns in PSI and 14 ± 2/ns in PSII.
藻胆体（PBS）作为主要的光收集系统，将激发能传递到蓝细菌和红藻中的两个光系统（PS）。已经在分离的系统和蓝细菌鱼腥藻 PCC 7120 的完整丝状体内研究了涉及激发能转移的皮秒动力学。提出了一个目标模型，该模型解决了不同发色团组的动力学问题。从棒到核心的能量转移速率为 8.5±1.0/ns，无论是在体内还是在体外，都是限速步骤。PBS-PSI-PSII 超复合物揭示了从 PBS 核心中的低能藻胆蛋白（末端发射器）到光系统中的叶绿素 a 的高效激发能迁移。藻胆体的末端发射器以 50±10/ns 的速率将能量传递给 PSI 和 PSII，将太阳能平均分配到两个光系统。最后，激发能通过在光系统中的电荷分离被捕获，估计在 PSI 中的捕获速率为 56±6/ns，在 PSII 中的捕获速率为 14±2/ns。
