Department of Physics, Concordia University , 7141 Sherbrooke Street West, Montreal, Quebec H4B 1R6, Canada.
Estacion Experimental de Aula Dei (CSIC) , Avda. Montañana 1005, 50059 Zaragoza, Spain.
J Phys Chem B. 2017 Oct 26;121(42):9848-9858. doi: 10.1021/acs.jpcb.7b07686. Epub 2017 Oct 13.
In non-photochemical spectral hole burning (NPHB) and spectral hole recovery experiments, cytochrome bf protein exhibits behavior that is almost independent of the deuteration of the buffer/glycerol glassy matrix containing the protein, apart from some differences in heat dissipation. On the other hand, strong dependence of the hole burning properties on sample preparation procedures was observed and attributed to a large increase of the electron-phonon coupling and shortening of the excited-state lifetime occurring when n-dodecyl β-d-maltoside (DM) is used as a detergent instead of n-octyl β-d-glucopyranoside (OGP). The data was analyzed assuming that the tunneling parameter distribution or barrier distribution probed by NPHB and encoded into the spectral holes contains contributions from two nonidentical components with accidentally degenerate excited state λ-distributions. Both components likely reflect protein dynamics, although with some small probability one of them (with larger md) may still represent the dynamics involving specifically the -OH groups of the water/glycerol solvent. Single proton tunneling in the water/glycerol solvent environment or in the protein can be safely excluded as the origin of observed NPHB and hole recovery dynamics. The intensity dependence of the hole growth kinetics in deuterated samples likely reflects differences in heat dissipation between protonated and deuterated samples. These differences are most probably due to the higher interface thermal resistivity between (still protonated) protein and deuterated water/glycerol outside environment.
在非光化学光谱烧孔（NPHB）和光谱烧孔恢复实验中，细胞色素 bf 蛋白的行为几乎与缓冲液/甘油玻璃基质的氘化无关，除了在散热方面存在一些差异。另一方面，观察到孔烧孔特性对样品制备程序强烈依赖，并归因于当使用正十二烷基 β-D-麦芽糖苷（DM）作为去污剂而不是辛基 β-D-吡喃葡萄糖苷（OGP）时，电子-声子耦合的大幅增加和激发态寿命的缩短。数据的分析假设，由 NPHB 探测的隧道参数分布或激发态 λ 分布的势垒分布包含两个非相同组件的贡献，这些组件的激发态 λ 分布偶然简并。这两个组件可能都反映了蛋白质动力学，尽管其中一个组件（具有更大的 md）可能仍然代表涉及水/甘油溶剂中 -OH 基团的动力学，其概率很小。可以安全地排除在水/甘油溶剂环境或蛋白质中单个质子的隧穿是观察到的 NPHB 和孔恢复动力学的起源。氘化样品中孔生长动力学的强度依赖性可能反映了质子化和氘化样品之间的散热差异。这些差异很可能是由于（仍然质子化的）蛋白质与外部环境中的氘化水/甘油之间的界面热阻较高所致。
