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.

中文翻译：

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模拟激发能量转移并捕获丝状蓝藻鱼腥藻PCC 7120。

藻胆体（PBS）是主要的光收集系统，将激发能集中到蓝细菌和红藻中的两个光系统（PS）中。已在分离的系统和完整的蓝藻鱼腥藻PCC 7120的细丝中研究了涉及激发能量转移的皮秒动力学。提出了一个目标模型，用于解析不同发色团的动力学。从棒到芯的能量转移速率为8.5±1.0 / ns是体内和体外的速率限制步骤。PBS-PSI-PSII超复合物揭示了有效的激发能从PBS核心中的末端发射体低能变藻蓝蛋白迁移到光系统中的叶绿素a的过程。藻胆体的末端发射体以50±10 / ns的速率将能量传递给PSI和PSII，将太阳能平均分配给两个光系统。最后，激发能通过光系统中的电荷分离被捕获，捕获速率在PSI中估计为56±6 / ns，在PSII中为14±2 / ns。