Department of Chemistry, Arizona State University, 85287-1604, Tempe, AZ, USA.
Photosynth Res. 1990 Jul;25(1):1-10. doi: 10.1007/BF00051730.
Fluorescence lifetimes have been measured for bacteriochlorophyll (BChl) c isolated from Chlorobium limicola in different states of aggregation in non-polar solvents. Two different homologs of BChl c were used, one with an isobutyl group at the 4 position, the other with n-propyl. Species previously identified as dimers (Olson and Pedersen 1990, Photosynth Res, this issue) decayed with lifetimes of 0.64 ns for the isobutyl homolog, 0.71 ns for n-propyl. Decay-associated spectra indicate that the absorption spectrum of the isobutyl dimer is slightly red-shifted from that of the n-propyl dimer. Aggregates absorbing maximally at 710 nm fluoresced with a principal lifetime of 3.1 ns, independent of the homolog used. In CCl4, only the isobutyl homolog forms a 747-nm absorbing oligomer spectrally similar to BChl c in vivo. This oligomer shows non-exponential fluorescence decay with lifetimes of 67 and 19 ps. Because the two components show different excitation spectra, the higher oligomer is probably a mixture of more than one species, both of which absorb at ∼747 nm.
已在非极性溶剂中测量了分离自嗜盐绿菌（Chlorobium limicola）的菌绿素 c（BChl c）在不同聚集态下的荧光寿命。使用了两种不同的 BChl c 同系物，一种在 4 位具有异丁基，另一种具有正丙基。先前被鉴定为二聚体的物种（Olson 和 Pedersen 1990，Photosynth Res，本期）的衰减寿命为异丁基同系物的 0.64 ns，正丙基同系物的 0.71 ns。与衰减相关的光谱表明，异丁基二聚体的吸收光谱略微红移，与正丙基二聚体不同。在 CCl4 中，只有异丁基同系物形成了一个 710nm 最大吸收的聚集体，其荧光主寿命为 3.1 ns，与使用的同系物无关。在 CCl4 中，只有异丁基同系物形成了一个 747nm 吸收的与活体中 BChl c 光谱相似的寡聚物。该寡聚物的荧光衰减表现为非指数衰减，寿命为 67 和 19 ps。由于这两个组分显示出不同的激发光谱，因此较高的寡聚物可能是多种物种的混合物，它们都在约 747nm 处吸收。
