Department of Chemistry/Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland.
Photochem Photobiol. 2012 May-Jun;88(3):675-83. doi: 10.1111/j.1751-1097.2012.01098.x. Epub 2012 Feb 17.
Excitation energy transfer in chlorosomes from photosynthetic green sulfur bacteria, Chlorobaculum (Cba.) tepidum and Prosthecochloris (Pst.) aestuarii, have been studied at room temperature by time-resolved femtosecond transient absorption spectroscopy. Bleach rise times from 117 to 270 fs resolved for both chlorosomes reflect extremely efficient intrachlorosomal energy transfer. Bleach relaxation times, from 1 to 3 ps and 25 to 35 ps, probed at 758 nm were tentatively assigned to intrachlorosomal energy transfer based on amplitude changes of the global fits and model calculations. The anisotropy decay constant of about 1 ps resolved at 807 nm probe wavelength for the chlorosomes from Chloroflexus aurantiacus, Pst. aestuarii and Cba. tepidum was related to energy transfer between bacteriochlorophyll a molecules of the baseplate and partly to intrachlorosomal energy transfer. The longer anisotropy components 6.6, 8.8 and 12.1 ps resolved for the three chlorosomes, respectively, were assigned to chlorosome to baseplate energy transfer. Global fits of magic-angle data also revealed longer chlorosome to baseplate energy transfer components from 95 to 135 ps, in accord with results from simulations.
在室温下，通过时间分辨飞秒瞬态吸收光谱研究了光合作用绿硫细菌 Chlorobaculum (Cba.) tepidum 和 Prosthecochloris (Pst.) aestuarii 的叶绿素体中的激发能量转移。两种叶绿素体的漂白上升时间从 117 到 270 fs 确定，反映了极其有效的叶绿素体内部能量转移。在 758nm 处探测到的漂白弛豫时间，从 1 到 3 ps 和 25 到 35 ps，根据全局拟合和模型计算的幅度变化，推测是基于叶绿素体内部能量转移。在 807nm 探测波长下，Chloroflexus aurantiacus、Pst. aestuarii 和 Cba. tepidum 的叶绿素体的各向异性衰减常数约为 1 ps，与基片上细菌叶绿素 a 分子之间的能量转移有关，部分与叶绿素体内部能量转移有关。对于这三个叶绿素体，分别解析出更长的各向异性分量 6.6、8.8 和 12.1 ps，分别被分配到叶绿素体到基片的能量转移。魔法角数据的全局拟合也揭示了更长的叶绿素体到基片的能量转移分量，从 95 到 135 ps，与模拟结果一致。
