Appearance of the v(FeIV = O) vibration from a ferryl-oxo intermediate in the cytochrome oxidase/dioxygen reaction.
Appearance of the v(FeIV = O) vibration from a ferryl-oxo intermediate in the cytochrome oxidase/dioxygen reaction.
复制标题
在细胞色素氧化酶/双氧反应中，ferr1-oxo 中间体出现 v(FeIV = O) 振动。
DOI：
10.1021/bi00484a001
复制
发表时间：
1990
期刊：
影响因子：
2.9
通讯作者：
Babcock,GT
中科院分区：
文献类型：
--
作者：
Varotsis,C;Babcock,GT
密歇根州立大学化学系和激光实验室，东兰辛，密歇根48824-1322接收于1990年5月9日;修订的手稿接收于1990年6月12日摘要：时间分辨共振拉曼光谱在室温下完全还原的（α 2 + α 2+）细胞色素氧化酶与分子氧反应过程中被记录下来。在一氧化碳光解后以800 ps记录的光谱中，在790 cm-1处观察到一个模式，当用1802重复实验时，该模式移动到755 cm-1。该振动的频率和1802同位素频移的幅度导致我们将790-CHT 1模式分配给在完全还原的细胞色素氧化酶与分子氧的反应中发生的铁酰基-氧代细胞色素a3中间体的FeIV= 0伸缩振动。当D20用作溶剂时，该模式的出现和振动频率不受影响。该结果表明铁酰基-氧代中间体不是氢键键合的。我们还记录了在氧化酶/O2反应期间高频（1000-1700 cm-1）区域中的拉曼光谱，其表明细胞色素α 2+的氧化是双相的。更快的阶段是在100 ps内完成，然后是一个平台区，其中没有进一步的氧化细胞色素a发生。平台持续到~ 500 ps，然后是氧化的第二阶段。细胞色素a的氧化还原活性的动力学的这些结果与希尔等人讨论的分支途径是一致的。[Hill，B.，格林伍德角，& Nichols，P.（1986）Biochim. Biophys. Acta 853，91-113]用于在室温下通过O2氧化还原的细胞色素氧化酶。
Department of Chemistry and the Laser Laboratory, Michigan State University, East Lansing, Michigan 48824-1322 Received May 9, 1990; Revised Manuscript Received June 12, 1990 abstract: Time-resolved resonance Raman spectrahave been recorded during the reaction offully reduced (a2+ a2+) cytochrome oxidase with dioxygen at room temperature. In the spectrum recorded at 800 ps subsequent to carbon monoxide photolysis, a mode is observed at 790 cm'1 that shifts to 755cm" 1 when the experiment is repeated with 1802. The frequency of this vibration and the magnitude of the 1802 isotopic frequency shift lead us to assign the 790-cm" 1 mode to the FeIV= 0 stretching vibration of a ferryl-oxo cytochrome a3 intermediate that occurs in the reaction of fully reduced cytochrome oxidase with dioxygen. The appearance and vibrational frequency of this mode were not affected when D20 was used as a solvent. This result suggests that the ferryl-oxo intermediate is not hydrogen bonded. We have also recorded Raman spectra in the high-frequency (1000-1700 cm'1) region during the oxidase/02 reaction that show that the oxidation of cytochrome a2+ is biphasic. The faster phase is complete within 100 ps and is followed by a plateau region in which no further oxidation of cytochrome a occurs. The plateau persists to~ 500 ps and is followed by the second phase of oxidation. These results on the kinetics of the redox activity of cytochrome a are consistent with the branched pathway discussed by Hill et al.[Hill, B., Greenwood, C., & Nichols, P.(1986) Biochim. Biophys. Acta 853, 91-113] for the oxidation of reduced cytochrome oxidase by 02 at room temperature.