Department of Biophysics, Huygens Laboratory, Leiden University, P.O. Box 9504, 2300 RA, Leiden, The Netherlands.
Photosynth Res. 1994 Jul;41(1):193-203. doi: 10.1007/BF02184160.
The pigment composition and energy transfer pathways in isolated chlorosomes ofChlorobium phaeovibrioides andChlorobium vibrioforme were studied by means of high performance liquid chromatography (HPLC) and picosecond absorbance difference spectroscopy. Analysis of pigment extracts of the chlorosomes revealed that they contain small amounts of bacteriochlorophyll (BChl)a esterified with phytol, whereas the BChlsc, d ande are predominantly esterified with farnesol. The chlorosomal BChla content inC. phaeovibrioides andC. vibrioforme was found to be 1.5% and 0.9%, respectively. The time resolved absorbance difference spectra showed a bleaching shifted to longer wavelengths as compared to the Qy absorption maxima and in chlorosomes ofC. vibrioforme also an absorbance increase at shorter wavelengths was observed. These spectral features were ascribed to excitation of oligomers of BChle and BChlc/d, respectively. 'One-color' and 'two-color' pump-probe kinetics ofC. phaeovibrioides showed rapid energy transfer to long-wavelength absorbing BChle oligomers, followed by trapping of excitations by BChla with a time constant of about 60 ps. Time resolved anisotropy measurements inC. vibrioforme showed randomization of excitations among BChla molecules with a time constant of about 20 ps, indicating that BChla in the baseplate is organized in clusters. One-color and two-color pump-probe measurements inC. vibrioforme showed rapid energy transfer from short-wavelength to long-wavelength absorbing oligomers with a time constant of about 11 ps. Trapping of excitations by BChla in this species could not be resolved unambiguously due to annihilation processes in the BChla clusters, but may occur with time constants of 15, 70 and 200 ps.
采用高效液相色谱（HPLC）和皮秒吸收差光谱法研究了分离的绿菌属（Chlorobium）phaevibrioides 和绿菌属（Chlorobium）vibrioforme 中叶绿素体的色素组成和能量转移途径。对叶绿素体色素提取物的分析表明，它们含有少量用植醇酯化的细菌叶绿素（BChl）a，而 BChlsc、d 和 e 主要用法呢醇酯化。在 C.phaevibrioides 和 C.vibrioforme 中发现叶绿素体 BChla 的含量分别为 1.5%和 0.9%。时间分辨吸收差光谱显示，与 Qy 吸收最大值相比，漂白向较长波长移动，并且在 C.vibrioforme 的叶绿素体中也观察到较短波长处的吸收增加。这些光谱特征分别归因于 BChle 和 BChlc/d 寡聚物的激发。“单波长”和“双波长”泵浦探测动力学研究表明，C.phaevibrioides 中的快速能量转移到长波长吸收的 BChle 寡聚物，随后通过 BChla 以约 60 ps 的时间常数捕获激发。在 C.vibrioforme 中进行的时间分辨各向异性测量表明，激发在 BChla 分子之间随机化，时间常数约为 20 ps，表明基底片中的 BChla 以簇的形式组织。在 C.vibrioforme 中进行的单波长和双波长泵浦探测测量表明，能量从短波长快速转移到长波长吸收的寡聚物，时间常数约为 11 ps。由于 BChla 簇中的湮灭过程，无法明确分辨该物种中 BChla 对激发的捕获，但可能以 15、70 和 200 ps 的时间常数发生。
