Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands.
Max-Planck-Institut für Chemische Energiekonversion, D-45470 Mülheim a.d. Ruhr, Germany.
Int J Mol Sci. 2024 Apr 8;25(7):4125. doi: 10.3390/ijms25074125.
We establish a general kinetic scheme for the energy transfer and radical-pair dynamics in photosystem I (PSI) of , PCC6803, and grown under white-light conditions. With the help of simultaneous target analysis of transient-absorption data sets measured with two selective excitations, we resolved the spectral and kinetic properties of the different species present in PSI. WL-PSI can be described as a Bulk Chl in equilibrium with a higher-energy Chl one or two Red Chl and a reaction-center compartment (WL-RC). Three radical pairs (RPs) have been resolved with very similar properties in the four model organisms. The charge separation is virtually irreversible with a rate of ≈900 ns. The second rate, of RP1 → RP2, ranges from 70-90 ns and the third rate, of RP2 → RP3, is ≈30 ns. Since RP1 and the Red Chl are simultaneously present, resolving the RP1 properties is challenging. In , the excited WL-RC and Bulk Chl compartments equilibrate with a lifetime of ≈0.28 ps, whereas the Red and the Bulk Chl compartments equilibrate with a lifetime of ≈2.65 ps. We present a description of the thermodynamic properties of the model organisms at room temperature.
我们建立了一个普遍的动力学方案，用于在白光条件下研究蓝藻、PCC6803 和 中的光系统 I（PSI）中的能量转移和自由基对动力学。通过同时分析用两种选择性激发测量的瞬态吸收数据集，我们解决了 PSI 中存在的不同物种的光谱和动力学特性。WL-PSI 可以描述为与一个或两个高能 Chl、一个反应中心隔室（WL-RC）平衡的 Bulk Chl。在这四个模型生物中，已经分辨出了三个具有非常相似特性的自由基对（RP）。电荷分离几乎是不可逆的，速率约为 900ns。RP1→RP2 的第二个速率范围从 70-90ns，而 RP2→RP3 的第三个速率约为 30ns。由于 RP1 和 Red Chl 同时存在，因此解析 RP1 的性质具有挑战性。在 中，激发的 WL-RC 和 Bulk Chl 隔室通过 ≈0.28ps 的寿命达到平衡，而 Red 和 Bulk Chl 隔室通过 ≈2.65ps 的寿命达到平衡。我们提出了模型生物在室温下的热力学性质描述。
