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第二个球体对铁中基体-类似物结合的贡献(III) 超氧化物脱酶
Juan Xie1, Emine Yikilmaz, Anne-Frances Miller
1Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
Journal of the American Chemical Society
|April 4, 2002
概括
研究人员使用光谱学和计算研究了铁氧化物脱酶 (FeSOD) 化添加物. 他们发现了一个单一的化物联体,并提出Fe-N-N键角差异解释了这些重要的酶复合物的不同颜色.
科学领域:
- 生物化学 生物化学
- 生物有机化学 生物有机化学
- 计算化学计算化学
背景情况:
- 铁(III) 超氧化脱酶 (FeSOD) 对于细胞对反应性氧物种的防御至关重要.
- 低温的FeSOD的化添加物呈现出明显的黄色和粉红色的形式,其结构基础在20多年来一直不清楚.
研究的目的:
- 为了阐明黄色和粉红色的铁氧化物脱酶 (N(III) 氧化物脱酶 (N(3) -FeSOD) 的黄色和粉红色氧化物添加物的结构和电子特性.
- 解决关于化物配体数量的差异,并了解导致光谱变异的因素.
主要方法:
- 可变温度,可变场的磁圆二元化 (MCD) 光谱学.
- 共振拉曼 (RR) 光谱学.共振拉曼 (RR) 光谱学.
- 密度函数理论 (DFT) 和半实证的INDO/S-CI计算建模.
主要成果:
- 谱学数据表明,在黄色和粉红色的N(3) -FeSOD物种中,单一的亚酸连接到铁中心,挑战了先前的假设.
- 共振拉曼光谱揭示了Fe-N(3) 结合的微妙差异,在野生类型和Q69E突变形式中一致.
- 计算研究支持单一的阿齐德模型,并将光谱变化归因于Fe-N-N键角差异的差异,约10°的变化解释了颜色差异.
结论:
- N(3) -FeSOD附加物的独特颜色源于Fe-N-N键角的变化,受到第二个协调球的影响.
- 第二个协调球体在调节活性部位的几何结构和潜在的基质定向方面发挥着作用,用于酶活性.
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