RESONANCE RAMAN STUDIES OF ESCHERICHIA-COLI SULFITE REDUCTASE HEMOPROTEIN .3. BOUND LIGAND VIBRATIONAL-MODES
RESONANCE RAMAN STUDIES OF ESCHERICHIA-COLI SULFITE REDUCTASE HEMOPROTEIN .3. BOUND LIGAND VIBRATIONAL-MODES
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DOI：
10.1021/bi00439a024
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发表时间：
1989-06-27
期刊：
影响因子：
2.9
通讯作者：
SPIRO, TG
中科院分区：
文献类型：
--
作者：
HAN, SW;MADDEN, JF;SPIRO, TG
利用共振拉曼光谱研究了大肠杆菌亚硫酸盐还原酶血红蛋白在不同氧化还原状态下结合的双原子血红素配体CO、CN-和NO的振动，并利用同位素标记的配体产生了配位。对于室温下完全还原的CO配合物（铁血红素，还原的Fe4S4簇），.nu。CO在1904 cm-1被观察到，在团簇氧化后转移到1920 cm-1。在574 cm-1和566 cm-1处，通过其同位素的“之”字形变化，分别确定了对应的δ - feco模式。在冷冻溶液中，观察到两种团簇氧化态，其中。CO在1910年和1936年cm-1和。nu。FeC分别为532和504 cm-1；.nu。在冻结状态下，完全还原物种的FeC在526 cm-1处被确定。对于亚铁siro血红素- no络合物（簇氧化），.nu。在冷冻溶液中，NO在1555 cm-1处被识别，低频模式在558 cm-1处被识别；这种拉伸模式明显低于Mb-No。对于铁siroheme -氰配合物，观察到两种配体键形式的证据，模式为451/390和451/352 cm-1；它们的特征是上模和下模的同位素移位模式的反转，可能分别来自线性和弯曲的Fe-C-N单元。在495和452 cm-1处观察到的铁铁siroheme -氰配合物的同位素敏感模式分别属于fen -弯曲振动和FeC -拉伸振动。考虑了这些结合配体光谱异常特征的可能来源。根据还原的CO种类与辣根过氧化物酶的CO加合物的h键形式的相似性，远端氢键可能有助于这些影响。
The vibrations of the bound diatomic heme ligands CO, CN-, and NO are investigated by resonance Raman spectroscopy in various redox states of Escherichia coli sulfite reductase hemoprotein, and assignments are generated by use of isotopically labeled ligands. For the fully reduced CO complex (ferrous siroheme, reduced Fe4S4 cluster) at room temperature, .nu.CO is observed at 1904 cm-1, shifting to 1920 cm-1 upon oxidation of the cluster. The corresponding .delta.FeCO modes are identified at 574 and 566 cm-1, respectively, by virtue of the zigzag pattern of their isotopic shifts. In frozen solution, two species are observed for the cluster-oxidized state, with .nu.CO at 1910 and 1936 cm-1 and .nu.FeC at 532 and 504 cm-1, respectively; .nu.FeC for the fully reduced species is identified at 526 cm-1 in the frozen state. For the ferrous siroheme-NO complex (cluster oxidized), .nu.NO is identified at 1555 cm-1 in frozen solution and a low-frequency mode is identified at 558 cm-1; this stretching mode is significantly lower than that observed in Mb-No. For the ferric siroheme cyanide complexes evidence of two ligand-bonding forms is observed, with modes at 451/390 and 451/352 cm-1; they are distinguished by a reversal of the isotopic shift patterns of the upper and lower modes and could arise from a linear and a bent Fe-C-N unit, respectively. For the ferrous siroheme cyanide complex isotope-sensitive modes observed at 495 and 452 cm-1 are assigned to the FeCN- bending and FeC stretching vibrations, respectively. The possible origin of unusual features of these bound ligand spectra is considered. Distal H-bonding may contribute to these effects, on the basis of the similarity of the reduced CO species to those of an H-bonded form of the CO adduct of horseradish peroxidase.