Department of Physics, Concordia University, 7141 Sherbrooke Street West, Montreal, Quebec H4B 1R6, Canada.
J Phys Chem B. 2010 Mar 18;114(10):3426-38. doi: 10.1021/jp9089358.
Previously published and new spectral hole burning (SHB) data on the B800 band of LH2 light-harvesting antenna complex of Rps. acidophila are analyzed in light of recent single photosynthetic complex spectroscopy (SPCS) results (for a review, see Berlin et al. Phys. Life Rev. 2007, 4, 64.). It is demonstrated that, in general, SHB-related phenomena observed for the B800 band are in qualitative agreement with the SPCS data and the protein models involving multiwell multitier protein energy landscapes. Regarding the quantitative agreement, we argue that the single-molecule behavior associated with the fastest spectral diffusion (smallest barrier) tier of the protein energy landscape is inconsistent with the SHB data. The latter discrepancy can be attributed to SPCS probing not only the dynamics of of the protein complex per se, but also that of the surrounding amorphous host and/or of the host-protein interface. It is argued that SHB (once improved models are developed) should also be able to provide the average magnitudes and probability distributions of light-induced spectral shifts and could be used to determine whether SPCS probes a set of protein complexes that are both intact and statistically relevant. SHB results are consistent with the B800 --> B850 energy-transfer models including consideration of the whole B850 density of states.
先前发表的和新的光谱烧孔（SHB）数据关于 LH2 光收集天线复合物的 B800 带 Rps. acidophila 是根据最近的单个光合复合物光谱（SPCS）结果进行分析的（综述见 Berlin 等人，《物理生命评论》2007 年，第 4 卷，第 64 页）。结果表明，一般来说，B800 带观察到的与 SHB 相关的现象与 SPCS 数据以及涉及多井多层次蛋白质能量景观的蛋白质模型定性一致。关于定量一致性，我们认为与蛋白质能量景观中最快光谱扩散（最小势垒）层相关的单分子行为与 SHB 数据不一致。后者的差异可以归因于 SPCS 不仅探测蛋白质复合物本身的动力学，还探测无定形周围宿主和/或宿主-蛋白质界面的动力学。有人认为，一旦开发出改进的模型，SHB（光谱烧孔）也应该能够提供光诱导光谱位移的平均幅度和概率分布，并可用于确定 SPCS 探针的一组蛋白质复合物是否完整且具有统计学意义。SHB 结果与包括考虑整个 B850 态密度的 B800 --> B850 能量转移模型一致。
