在与基质模拟物6 - 碳烯的转换过程中,Bacillus subtilis QueE中的一个中间基
Jarett Wilcoxen1, Nathan A Bruender2, Vahe Bandarian3
1Department of Chemistry, University of California, Davis , Davis, California 95616, United States.
Journal of the American Chemical Society
|January 6, 2018
概括
这项研究揭示了一种新型的基因中间体,该基因在6- carboxypterin (6- CP) 由7- carboxy-7- deazaguanine (CDG) 合成酶 (QueE) 的酶转化过程中被发现. 光谱证据证实了6-CP-dAdo基的形成,阐明了罗胺代谢物合成的新反应途径.
科学领域:
- 生物化学
- 酵素学
- 光谱学
背景情况:
- 7- 碳基-7- 脱氨酸 (CDG) 合成酶 (QueE) 是一种激进的S- 腺甲氨酸 (SAM) 酶.
- QueE催化了6 - 碳基-5,6,7,8- 四基 (CPH4) 转化为CDG,这是pyrrolopyrimidine代谢物合成的关键步骤.
- 激素SAM酶利用一个 [4Fe-4S] 集群来切割SAM,生成一个5'-脱氧基基用于基质修饰.
研究的目的:
- 研究QueE与替代基质6-碳素 (6-CP) 的反应机制.
- 提供与6-CP的QueE催化反应中建议的基质中间体的光谱证据.
- 确定中间基的电子结构的特征.
主要方法:
- 使用连续波和脉冲电子磁共振 (EPR) 光谱.
- 分析了酶反应中形成的基质中间体的电子结构.
- 研究了QueE,6-CP和5'-脱氧氨基基之间的相互作用.
主要成果:
- 呈现了6-CP-dAdo基中间体形成的光谱证据.
- 描述了这种新型激进物种的电子结构.
- 证实了一种涉及5'-dAdo·和6-CP的激素添加机制.
结论:
- 这项研究确定并描述了6-CP的QueE催化转化中的关键基质中间体.
- 这一发现为QueE和更广泛的SAM酶超级家族的反应机制提供了新的见解.
- 这些结果支持基质添加途径,其次是氧化脱碳化,以形成改性.
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