Picosecond resonance Raman spectroscopic evidence for excited-state spin conversion in carbonmonoxy-hemoglobin photolysis.
Picosecond resonance Raman spectroscopic evidence for excited-state spin conversion in carbonmonoxy-hemoglobin photolysis.
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碳单氧血红蛋白光解中激发态自旋转换的皮秒共振拉曼光谱证据。
DOI：
10.1073/pnas.78.3.1313
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发表时间：
1981
影响因子：
11.1
通讯作者：
M. El
中科院分区：
文献类型：
--
作者：
J. Terner;J. Stong;T. Spiro;M. Nagumo;M. Nicol;M. El
通过将同步抽模腔倒空染料激光器的30 ps脉冲紧紧聚焦在COHb溶液的喷射流上，利用共振拉曼光谱在皮秒时间尺度上研究了碳一氧血红蛋白（COHb）光产物的结构。光产物的光谱与脱氧血红蛋白的光谱相似，但1603 cm（-1）（去极化）、1552 cm（-1）（非极化）和1542 cm（-1）（去极化）的频率比脱氧血红蛋白的低2-4 cm（-1）。类似的低频率观察到一个物种被认为是双四氢呋喃加合物的Fe（II）octagethyl卟啉，含有面内高自旋Fe（II）。这些结果表明，在COHb光产物的Fe（II）已经是高自旋，但更接近血红素平面比脱氧血红蛋白。从五重配位场激发态的COHb的光解建议。当激光脉冲延长到20 ns时，相对于脱氧Hb的频率偏移持续存在。脱氧血红蛋白的完全平面外血红素构象的明显缓慢弛豫被认为与球蛋白三级结构的变化有关。
The structure of the carbonmonoxy-hemoglobin (COHb) photoproduct has been studied on the picosecond time scale with resonance Raman spectroscopy, by tightly focusing the 30-ps pulses of a synchronously pumped mode-locked cavitydumped dye laser on a jet stream of COHb solution. The spectrum of the photoproduct is similar to that of deoxy Hb, but the frequencies 1603 cm(-1) (depolarized), 1552 cm(-1) (anomalously polarized), and 1542 cm(-1) (depolarized) are 2-4 cm(-1) lower than those of deoxy Hb. Similar low frequencies are observed for a species believed to be the bis-tetrahydrofuran adduct of Fe(II) octaethylporphyrin, containing in-plane high-spin Fe(II). These results indicate that in the COHb photoproduct the Fe(II) is already high-spin but is closer to the heme plane than in deoxy Hb. Photodissociation from a quintet ligand-field excited state of COHb is suggested. The frequency shifts relative to deoxy Hb persist when the laser pulses are lengthened to 20 ns. The apparently slow relaxation to the fully out-of-plane heme conformation of deoxy Hb is suggested to be associated with change of the globin tertiary structure.