Jia Y, Jean J M, Werst M M, Chan C K, Fleming G R
Department of Chemistry, University of Chicago, Illinois 60637.
Biophys J. 1992 Jul;63(1):259-73. doi: 10.1016/S0006-3495(92)81589-8.
In order to understand the organization of the PSI core antenna and to interpret results obtained from studies of the temperature and wavelength dependence of energy transfer and trapping in the PSI particles, we have constructed a model for PSI in which spectral heterogeneity is considered via a self-consistent approach based on Forster transport. The temperature dependence of the absorption and emission spectra of the individual Chl molecules in the protein matrix is calculated based on a model Hamiltonian which includes a phonon contribution. Time and wavelength resolved kinetics of PSI at different temperatures are investigated by means of two-dimensional lattice models. We conclude that wavelength-dependent fluorescence decay kinetics result only when two or more bottlenecks exist in the energy transfer and trapping process. A single trap or several pseudo-traps with spectrally identical environments do not lead to wavelength dependent decays. Simple funnel arrangements of the spectral types can be ruled out. At least one pigment with energy lower than the photochemical trap located close to the reaction center is required to produce the trends of the fluorescence lifetimes observed experimentally. The remainder of the core antenna is consistent with a random arrangement of spectral types.
为了理解光合系统I（PSI）核心天线的组织方式，并解释从PSI颗粒中能量转移和捕获的温度及波长依赖性研究中获得的结果，我们构建了一个PSI模型，其中通过基于福斯特传输的自洽方法考虑光谱异质性。基于包含声子贡献的模型哈密顿量，计算了蛋白质基质中单个叶绿素（Chl）分子吸收和发射光谱的温度依赖性。通过二维晶格模型研究了不同温度下PSI的时间和波长分辨动力学。我们得出结论，只有当能量转移和捕获过程中存在两个或更多瓶颈时，才会产生波长依赖性荧光衰减动力学。单个陷阱或几个具有光谱相同环境的伪陷阱不会导致波长依赖性衰减。光谱类型的简单漏斗状排列可以排除。为了产生实验观察到的荧光寿命趋势，需要至少一种能量低于位于反应中心附近的光化学陷阱的色素。核心天线的其余部分与光谱类型的随机排列一致。
