对catchol 1,2-dioxygenase的无氧酶基质复合物的光谱研究
Geoff P Horsman1, Andrew Jirasek, Frédéric H Vaillancourt
1Department of Biochemistry, The University of British Columbia, Vancouver, Canada.
Journal of the American Chemical Society
|December 1, 2005
概括
这项研究揭示了catechol以dianion的形式与铁结合在内二氧化酶中,与外酶不同. 这一发现得到了光谱学和DFT的支持,澄清了酶机制和基质结合.
科学领域:
- 生物化学和光谱学 生物化学和光谱学
- 酶的机制 酶的机制
- 生物有机化学 生物有机化学
背景情况:
- 内醇和外醇二氧化原酶的区域特异性尚未得到充分理解.
- 之前的研究表明,catechol在外醇二氧化原酶中以单离子的形式结合.
- 甲基醇的质子化状态是酶特异性的潜在因素.
研究的目的:
- 为了研究catechol在catechol 1,2-dioxygenase (C12O) 中的结合状态,一个内二氧化酶.
- 为了比较内醇与外醇二氧化原酶中的甲基醇结合.
- 阐明连接体转化效应在酶催化中的作用.
主要方法:
- 紫外线共振拉曼 (UVRR) 光谱学
- 紫外线可见 (UV-vis) 差异光谱学
- 密度函数理论 (DFT) 的计算.
- 模型化合物分析 (铁三酸盐和铁酸盐)
主要成果:
- 甲基醇与Fe (III) 结合,作为甲基醇1,2-二氧化原酶中的一个二离子体.
- 在290nm (UV-vis) 和1550cm(-1) (UVRR) 的光谱特征证实了dianionic catechol的结合.
- 铁酸连体质子和其转变效应影响基质不对称性和催化.
- DFT计算支持光谱赋值和机械洞察力.
结论:
- 甲基甲醇1,2-二氧化酶将甲基甲醇结合为二离子,与外醇二氧化酶形成鲜明对比.
- 体转变效应,特别是来自铁酸盐,在内二氧化原酶活性中起着至关重要的作用.
- 结合UVRR和UV-vis光谱仪是研究酶中的金属结合的有效方法.
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