Picosecond time-resolved resonance Raman studies of hemoglobin: implications for reactivity.
Picosecond time-resolved resonance Raman studies of hemoglobin: implications for reactivity.
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DOI：
10.1126/science.4023704
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发表时间：
1985-08
期刊：
影响因子：
56.9
通讯作者：
E. Findsen;J. Friedman;M. Ondrias;S. Simon
中科院分区：
文献类型：
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作者：
E. Findsen;J. Friedman;M. Ondrias;S. Simon
报告了用蓝色脉冲（20 至 30 皮秒）生成的血红蛋白的皮秒时间分辨拉曼光谱，该脉冲与 Soret 谱带共振，并且具有足够的强度以完全光解离起始配体样品。对于 R 态和 T 态配体血红蛋白，脱氧瞬态光谱中的峰值频率在大约 25 皮秒处与光解离后 10 纳秒处观察到的峰值频率相同。特别是，在先前报道的纳秒分辨光谱中检测到的铁近端组氨酸键（VFe-His）拉伸模式频率的巨大 R-T 差异在皮秒分辨光谱中也很明显。讨论了这一发现对于配体蛋白中应变能的分布和成对重组时间过程的起源的影响。基于这些结果，提出了一个微观模型，其中应变能的离域与铁的坐标强耦合。该模型用于解释配体解离速率中 R-T 差异的起源。
Picosecond time-resolved Raman spectra of hemoglobin generated with blue pulses (20 to 30 picoseconds) that were resonant with the Soret band and of sufficient intensity to completely photodissociate the starting liganded sample are reported. For both R- and T-state liganded hemoglobins, the peak frequencies in the spectrum of the deoxy transient were the same at approximately 25 picoseconds as those observed at 10 nanoseconds subsequent to photodissociation. In particular, the large R-T differences in the frequency of the stretching mode for the iron-proximal histidine bond (VFe-His) detected in previously reported nanosecond-resolved spectra were also evident in the picosecond-resolved spectra. The implications of this finding with respect to the distribution of strain energy in the liganded protein and the origin of the time course for geminate recombination are discussed. On the basis of these results, a microscopic model is proposed in which delocalization of strain energy is strongly coupled to the coordinate of the iron. The model is used to explain the origin of the R-T differences in the rates of ligand dissociation.