Wohlleben Wendel, Buckup Tiago, Herek Jennifer L, Cogdell Richard J, Motzkus Marcus
Max-Planck-Institut für Quantenoptik, Garching, Germany.
Biophys J. 2003 Jul;85(1):442-50. doi: 10.1016/S0006-3495(03)74489-0.
A new channel of excitation energy deactivation in bacterial light harvesting was recently discovered, which leads to carotenoid triplet population on an ultrafast timescale. Here we show that this mechanism is also active in LH2 of Rhodopseudomonas acidophila through analysis of transient absorption data with an evolutionary target analysis. The algorithm offers flexible testing of kinetic network models with low a priori knowledge requirements. It applies universally to the simultaneous fitting of target state spectra and rate constants to time-wavelength-resolved data. Our best-fit model reproduces correctly the well-known cooling and decay behavior in the S(1) band, but necessitates an additional, clearly distinct singlet state that does not exchange with S(1), promotes ultrafast triplet population and participates in photosynthetic energy transfer.
最近发现了细菌光捕获中激发能失活的一种新途径，这导致类胡萝卜素三重态在超快时间尺度上形成。在这里，我们通过用进化目标分析方法分析瞬态吸收数据表明，这种机制在嗜酸红假单胞菌的LH2中也很活跃。该算法对动力学网络模型进行灵活测试，且对先验知识要求较低。它普遍适用于将目标态光谱和速率常数同时拟合到时间-波长分辨数据。我们的最佳拟合模型正确地再现了S(1)带中众所周知的冷却和衰减行为，但需要一个额外的、明显不同的单重态，该单重态不与S(1)交换，促进超快三重态形成并参与光合能量转移。
