Vos M H, Jones M R, Hunter C N, Breton J, Martin J L
Laboratoire d'Optique Appliquée, Ecole Polytechnique-Ecole Nationale Supérieure de Techniques Avancées, Palaiseau, France.
Proc Natl Acad Sci U S A. 1994 Dec 20;91(26):12701-5. doi: 10.1073/pnas.91.26.12701.
A room-temperature study is reported of the femtosecond spectral evolution of the stimulated emission band of the primary electron-transfer precursor P* in bacterial photosynthesis. The study was performed with membranes of the antenna-deficient RCO1 mutant of Rhodobacter sphaeroides. A time-dependent red shift, reflecting nuclear motion out of the Franck-Condon region of the excited state, is resolved. Analysis of oscillatory features persisting for > 1 ps in the kinetics revealed main frequencies of the activated motions at 30, 84, 145, and 192 cm-1. The oscillations occur on the time scale of primary electron transfer. Our results set a lower limit for the vibrational dephasing time in P* that is not compatible with the usual assumption in theoretical treatments of complete vibrational relaxation prior to electron transfer, even at room temperature.
报道了一项关于细菌光合作用中初级电子转移前体P受激发射带飞秒光谱演化的室温研究。该研究使用了球形红杆菌天线缺陷型RCO1突变体的膜进行。解析出了反映核运动离开激发态弗兰克-康登区域的随时间变化的红移。对动力学中持续超过1皮秒的振荡特征进行分析，揭示了激活运动的主要频率为30、84、145和192厘米-1。这些振荡发生在初级电子转移的时间尺度上。我们的结果为P中的振动退相时间设定了下限，这与理论处理中通常假设的在电子转移之前完全振动弛豫不相符，即使在室温下也是如此。
