Kunz Ralf, Timpmann Kõu, Southall June, Cogdell Richard J, Freiberg Arvi, Köhler Jürgen
Experimental Physics IV and Bayreuth Institute for Macromolecular Research (BIMF), University of Bayreuth, Bayreuth, Germany.
Institute of Physics, University of Tartu, Tartu, Estonia.
Biophys J. 2014 May 6;106(9):2008-16. doi: 10.1016/j.bpj.2014.03.023.
We have recorded fluorescence-excitation and emission spectra from single LH2 complexes from Rhodopseudomonas (Rps.) acidophila. Both types of spectra show strong temporal spectral fluctuations that can be visualized as spectral diffusion plots. Comparison of the excitation and emission spectra reveals that for most of the complexes the lowest exciton transition is not observable in the excitation spectra due to the cutoff of the detection filter characteristics. However, from the spectral diffusion plots we have the full spectral and temporal information at hand and can select those complexes for which the excitation spectra are complete. Correlating the red most spectral feature of the excitation spectrum with the blue most spectral feature of the emission spectrum allows an unambiguous assignment of the lowest exciton state. Hence, application of fluorescence-excitation and emission spectroscopy on the same individual LH2 complex allows us to decipher spectral subtleties that are usually hidden in traditional ensemble spectroscopy.
我们记录了嗜酸红假单胞菌（Rps.）中单个LH2复合物的荧光激发光谱和发射光谱。这两种光谱都显示出强烈的时间光谱波动，可将其可视化为光谱扩散图。激发光谱和发射光谱的比较表明，由于检测滤光片特性的截止，对于大多数复合物来说，在激发光谱中无法观察到最低的激子跃迁。然而，从光谱扩散图中我们掌握了完整的光谱和时间信息，并且可以选择那些激发光谱完整的复合物。将激发光谱中最红的光谱特征与发射光谱中最蓝的光谱特征相关联，可以明确地确定最低激子态。因此，对同一个体的LH2复合物应用荧光激发光谱和发射光谱，使我们能够解读通常隐藏在传统系综光谱中的光谱细微差别。
