Kalinin Stanislav V, Molotkovsky Julian G, Johansson Lennart B A
Department of Chemistry, Biophysical Chemistry, Umeå University, Sweden.
Spectrochim Acta A Mol Biomol Spectrosc. 2002 Mar 15;58(5):1087-97. doi: 10.1016/s1386-1425(01)00613-8.
A theoretical model is presented, tested and applied for determining the rates of energy migration and distances within pairs of chemically identical fluorophores, so-called donors (D), which are exposed to different physical properties. The model is a general extension of the recently developed donor-donor energy migration (DDEM) model [J. Chem. Soc., Faraday Trans. 92 (1996)1563; J. Chem. Phys. 105 (1996) 10896] that applies to examining structure-function of biomacromolecules, such as proteins. Most fluorescent groups of the same kind incorporated at different positions (alpha and beta) in a macromolecule exhibit shifts of the absorption and/or emission spectra, as well as different relaxation rates of the photophysics. As a consequence, the energy migration between the D(alpha) and D(beta) groups will be partially reversible. We refer to this case, as the partial donor-donor energy migration (PDDEM). The models of PPDEM presented can be used for analysing time-resolved fluorescence relaxation, as well as fluorescence depolarisation experiments. To explore the limitations of the PDDEM model, we have generated and re-analysed synthetic data that mimic time-correlated single photon counting (TCSPC) experiments. It was found that slow and fast rates of energy migration are most accurately recovered from the fluorescence relaxation and the depolarisation experiments, respectively. At comparable transfer and fluorescence rates, both kinds of experiments are equally useful. Real experiments on PDDEM were performed on an asymmetrically quenched bichromophoric molecule (1,32-dihydroxy-dotriacontane-bis-(Rhodamine 101) ester), that spans across the lipid bilayer of a vesicle. The depolarisation data were analysed by the PDDEM model and provide a distance between Rhodamine 101 groups, which agrees with independent studies.
提出了一种理论模型，对其进行了测试并应用于确定化学性质相同的荧光团对（即所谓的供体（D））之间的能量迁移速率和距离，这些供体具有不同的物理性质。该模型是最近开发的供体-供体能量迁移（DDEM）模型[《化学学会杂志，法拉第汇刊》92 (1996) 1563；《化学物理杂志》105 (1996) 10896]的一般扩展，该模型适用于研究生物大分子（如蛋白质）的结构-功能。在大分子中不同位置（α和β）掺入的大多数同类荧光基团表现出吸收和/或发射光谱的位移，以及光物理的不同弛豫速率。因此，D(α)和D(β)基团之间的能量迁移将部分可逆。我们将这种情况称为部分供体-供体能量迁移（PDDEM）。所提出的PPDEM模型可用于分析时间分辨荧光弛豫以及荧光去极化实验。为了探索PDDEM模型的局限性，我们生成并重新分析了模拟时间相关单光子计数（TCSPC）实验的合成数据。结果发现，分别从荧光弛豫和去极化实验中最准确地恢复了慢和快的能量迁移速率。在可比的转移速率和荧光速率下，这两种实验同样有用。对跨越囊泡脂质双层的不对称猝灭双色团分子（1,32 - 二羟基 - 三十二烷 - 双 -（罗丹明101）酯）进行了关于PDDEM的实际实验。通过PDDEM模型分析去极化数据，并提供了罗丹明101基团之间的距离，这与独立研究结果一致。
