Vibrational spectrum of the lumi intermediate in the room temperature rhodopsin photo-reaction.
Vibrational spectrum of the lumi intermediate in the room temperature rhodopsin photo-reaction.
复制标题
室温视紫红质光反应中 Lumi 中间体的振动光谱。
DOI：
10.1016/s0006-3495(98)77861-0
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发表时间：
1998
影响因子：
3.4
通讯作者：
Atkinson,GH
中科院分区：
文献类型：
--
作者：
Ujj,L;Jäger,F;Atkinson,GH
利用皮秒时间分辨相干反斯托克斯拉曼光谱首次测量了在室温视紫红质光反应微秒时间范围内形成的光视紫质中间体的振动光谱(650-1750 cm−1)。在3ps，500 nm的RRRT激发下，记录到了2.5pS S的LUMI振动光谱。这些PTR/CARS结果补充了在足以冻结流明的Rh样品温度下记录的傅里叶变换红外光谱，通过识别21个谱带，首次提供了室温流明振动自由度(LumiRT)的详细信息。氢离面(环状)带的异常低强度(与在baoRT中观察到的相比)、C-C伸缩带的中等强度和绝对位置以及高强度CC伸展带的存在表明LumiRT包含几乎平面(非扭曲)的、全经视网膜的几何结构。独立地，最强烈的环状带的944厘米−1位置意味着在平面外的视网膜振动和组成视网膜结合袋的氨基酸中的至少一个基团之间存在共振耦合。通过记录在纳秒时间尺度上的PTR/CARS光谱监测到LumiRT的形成，可以与与BaToRT中间体平衡形成的蓝移中间体(BSIRT)的衰变有关。在210 ns延迟测量的PTR/CARS光谱包含可归因于BSIRT的明显振动特征，这表明BSIRT和LumiRT中的全经视网膜与视网膜结合袋的一部分强烈耦合。关于RhRT的能量存储/转导机制，这些结果支持了这样的假设，即在LumiRT的形成过程中，RhRT吸收的大部分光子能量转移到了凋亡蛋白opsin。
The vibrational spectrum (650–1750cm−1) of the lumi-rhodopsin (lumi) intermediate formed in the microsecond time regime of the room-temperature rhodopsin (RhRT) photoreaction is measured for the first time using picosecond time-resolved coherent anti-Stokes Raman spectroscopy (PTR/CARS). The vibrational spectrum of lumi is recorded 2.5μs after the 3-ps, 500-nm excitation of RhRT. Complementary to Fourier transform infrared spectra recorded at Rh sample temperatures low enough to freeze lumi, these PTR/CARS results provide the first detailed view of the vibrational degrees of freedom of room-temperature lumi (lumiRT) through the identification of 21 bands. The exceptionally low intensity (compared to those observed in bathoRT) of the hydrogen out-of-plane (HOOP) bands, the moderate intensity and absolute positions of C-C stretching bands, and the presence of high-intensity CC stretching bands suggest that lumiRTcontains an almost planar (nontwisting), all-transretinal geometry. Independently, the 944-cm−1position of the most intense HOOP band implies that a resonance coupling exists between the out-of-plane retinal vibrations and at least one group among the amino acids comprising the retinal binding pocket. The formation of lumiRT, monitored via PTR/CARS spectra recorded on the nanosecond time scale, can be associated with the decay of the blue-shifted intermediate (BSIRT) formed in equilibrium with the bathoRTintermediate. PTR/CARS spectra measured at a 210-ns delay contain distinct vibrational features attributable to BSIRT, which suggest that the all-transretinal in both BSIRTand lumiRTis strongly coupled to part of the retinal binding pocket. With regard to the energy storage/transduction mechanism in RhRT, these results support the hypothesis that during the formation of lumiRT, the majority of the photon energy absorbed by RhRTtransfers to the apoprotein opsin.