Femtosecond coherent transient infrared spectroscopy of reaction centers from Rhodobacter sphaeroides.
Femtosecond coherent transient infrared spectroscopy of reaction centers from Rhodobacter sphaeroides.
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球形红杆菌反应中心的飞秒相干瞬态红外光谱。
DOI：
10.1073/pnas.91.22.10360
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发表时间：
1994
影响因子：
11.1
通讯作者：
Hochstrasser,RM
中科院分区：
文献类型：
--
作者：
Maiti,S;Walker,GC;Cowen,BR;Pippenger,R;Moser,CC;Dutton,PL;Hochstrasser,RM
利用飞秒（300-400 fs）时间分辨红外（1560-1960 cm-1）光谱研究了与光合反应中心的光激发和电荷分离相关的蛋白质和辅因子振动动力学。实验处于相干瞬态极限，其中量子不确定性原理控制着蛋白质振动变化的演化。尽管电荷分离产生的电场改变了多肽羰基光谱，但电荷分离没有明显的蛋白质弛豫。从相干转移测量判断，“特殊对”P 和光激发单重态 P* 的势能面以及它们上的环境扰动是相似的。该区域中 P* 模式的振动相移时间为 600 fs。发现 1665 cm-1 的亚皮秒瞬态具有连续电子转移过程所需的动力学。参与光合作用初级步骤的所有其他瞬态中间体 P、P* 和 P+ 的动力学特征均在差异红外光谱中得到鉴定。
Protein and cofactor vibrational dynamics associated with photoexcitation and charge separation in the photosynthetic reaction center were investigated with femto-second (300-400 fs) time-resolved infrared (1560-1960 cm-1) spectroscopy. The experiments are in the coherent transient limit where the quantum uncertainty principle governs the evolution of the protein vibrational changes. No significant protein relaxation accompanies charge separation, although the electric field resulting from charge separation modifies the polypeptide carbonyl spectra. The potential energy surfaces of the "special pair" P and the photoexcited singlet state P* and environmental perturbations on them are similar as judged from coherence transfer measurements. The vibrational dephasing time of P* modes in this region is 600 fs. A subpicosecond transient at 1665 cm-1 was found to have the kinetics expected for a sequential electron transfer process. Kinetic signatures of all other transient intermediates, P, P*, and P+, participating in the primary steps of photosynthesis were identified in the difference infrared spectra.