DIRECT OBSERVATION OF THE FEMTOSECOND EXCITED-STATE CIS-TRANS ISOMERIZATION IN BACTERIORHODOPSIN
DIRECT OBSERVATION OF THE FEMTOSECOND EXCITED-STATE CIS-TRANS ISOMERIZATION IN BACTERIORHODOPSIN
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DOI：
10.1126/science.3363359
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发表时间：
1988-05-06
期刊：
影响因子：
56.9
通讯作者：
SHANK, CV
中科院分区：
文献类型：
--
作者：
MATHIES, RA;CRUZ, CHB;SHANK, CV
利用飞秒光学测量技术研究了光驱动跨膜质子泵细菌视紫红质的主要光过程。利用618纳米的60飞秒泵浦脉冲激发适应光的细菌视紫红质，利用6飞秒探针脉冲在-50 ~ 1000飞秒范围内记录了560 ~ 710纳米的瞬态吸收光谱。在60飞秒时，在吸收光谱中出现了一个宽的瞬态空穴，其振幅保持不变约200飞秒。660- 710纳米区域的受激发射和560- 580纳米区域的激发态吸收迅速出现，然后从0到。apprx发生位移和衰减。150飞秒。这些光谱特征提供了对激发态电位表面视网膜发色团的13-反式到13-顺式扭转异构化的直接观察。主要基态光产物J引起的吸收出现的时间常数约为。500飞秒。
Femtosecond optical measurement techniques have been used to study the primary photoprocesses in the light-driven transmembrane proton pump bacteriorhodopsin. Light-adapted bacteriorhodopsin was excited with a 60-femtosecond pump pulse at 618 nanometers, and the transient absorption spectra from 560 to 710 nanometers were recorded from -50 to 1000 femtoseconds by means of 6-femtosecond probe pulses. By 60 femtoseconds, a broad transient hole appeared in the absorption spectrum whose amplitude remained constant for about 200 femtoseconds. Stimulated emission in the 660- to 710-nanometer region and excited-state absorption in the 560- to 580-nanometer region appeared promptly and then shifted and decayed from 0 to .apprx. 150 femtoseconds. These spectral features provide a direct observation of the 13-trans to 13-cis torsional isomerization of the retinal chromophore on the excited-state potential surface. Absorption due to the primary ground-state photoproduct J appears with a time constant of .apprx. 500 femtoseconds.