The photocycle and ultrafast vibrational dynamics of bacteriorhodopsin in lipid nanodiscs
The photocycle and ultrafast vibrational dynamics of bacteriorhodopsin in lipid nanodiscs
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DOI：
10.1039/c4cp01826e
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发表时间：
2014-10-21
影响因子：
3.3
通讯作者：
Miller, R. J. Dwayne
中科院分区：
文献类型：
--
作者：
Johnson, Philip J. M.;Halpin, Alexei;Miller, R. J. Dwayne
利用稳态光谱和时间分辨光谱研究了脂纳米盘微环境中细菌视紫红质的光循环和振动动力学。线性吸收和圆二色性表明，nanodisks不扰动的视网膜结合口袋的结构，而瞬态吸收和闪光光解测量表明，光循环的质子泵的基础是不变的，从本机紫色膜。随后通过超快宽带瞬态吸收光谱研究了初始光中间体形成期间的振动动力学，其中由脂质纳米盘微环境提供的低散射允许通过感兴趣的频率区域的傅立叶滤波和随后的时域分析检索的振动动力学来明确地分配基态和激发态核动力学。正则基态振荡对应于高频乙烯和C-C伸缩，甲基岩石，和氢的面外摆动被检索，白色大振幅，短失相时间的振动主要恢复在频率区域与面外动力学和低频扭转模式牵连异构化。
The photocycle and vibrational dynamics of bacteriorhodopsin in a lipid nanodisc microenvironment have been studied by steady-state and time-resolved spectroscopies. Linear absorption and circular dichroism indicate that the nanodiscs do not perturb the structure of the retinal binding pocket, while transient absorption and flash photolysis measurements show that the photocycle which underlies proton pumping is unchanged from that in the native purple membranes. Vibrational dynamics during the initial photointermediate formation are subsequently studied by ultrafast broadband transient absorption spectroscopy, where the low scattering afforded by the lipid nanodisc microenvironment allows for unambiguous assignment of ground and excited state nuclear dynamics through Fourier filtering of frequency regions of interest and subsequent time domain analysis of the retrieved vibrational dynamics. Canonical ground state oscillations corresponding to high frequency ethylenic and C-C stretches, methyl rocks, and hydrogen out-of-plane wags are retrieved, white large amplitude, short dephasing time vibrations are recovered predominantly in the frequency region associated with out-of-plane dynamics and low frequency torsional modes implicated in isomerization.