在核糖核酸还原酶的氧化还原相关结构变化
A R Offenbacher1, I R Vassiliev, M R Seyedsayamdost
1Department of Chemistry and Biochemistry and the Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
Journal of the American Chemical Society
|June 4, 2009
概括
рибо核酸减少酶 (RNR) 使用铁基 (Y122*) 启动催化. 这项研究揭示了附近的氨基酸键的氧化还原连接结构变化,这是由基的静电变化驱动的.
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 频谱学是一种光谱学.
背景情况:
- рибо核酸减少酶 (RNR) 对于DNA合成至关重要,催化了脱氧核酸的产生.
- 像大肠杆菌β2亚单元一样,I类RNR具有铁中心和用于催化的关键铁自由基 (Y122*).
- 在Y122*中,氧依赖的形状变化可能调节质子合电子转移.
研究的目的:
- 调查与大肠杆菌β2.2中的Y122*基相关的氧化还原相关结构变化.
- 了解铁基在启动催化反应中的作用.
- 探索质子合电子转移调节的机制.
主要方法:
- 福利埃变换红外光谱法 (FT-IR) 用于检测反应诱导的光谱变化.
- 同位素标记用 (2) H ((4) 氨酸和 (15) N 氨酸有助于光谱分配.
- 差异光谱是在Y122*通过基尿素减少时获得的.
主要成果:
- FT-IR分析确定了与Y122 (1514 cm(-1)) 和Y122* (1498 cm(-1)) 相关的特定振动频段.
- 反应诱导的光谱显示了胺I波段的变化 (1661和1652 cm(-1)),表明结构变化.
- 这些胺带转移反映了在模型五中观察到的变化,表明了序列介导效应.
结论:
- Y122*的减少与附近的胺键的结构性扰动相结合.
- 这些结构变化受到围绕着铁基的氨基酸序列的影响.
- 一种拟议的机制涉及铁基的芳香环内与氧化还原相关的静电变化,导致胺键扰动.
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