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快速结灭磁性循环二元化X中介在核糖酸减少酶:新的结构洞察力

Natasa Mitić¹, Lana Saleh, Gerhard Schenk

¹Department of Chemistry, Stanford University, 333 Campus Street, Stanford, California 94305, USA.

Journal of the American Chemical Society

|October 14, 2005

概括

磁性循环二元化 (MCD) 揭示了在核糖核酸还原酶R2.2中中间X的电子结构. 这项研究区分了中间X的结构可能性,为氧气激活机制提供了新的见解.

科学领域:

生物化学生物化学
生物物理化学生物物理化学
频谱学是一种光谱学.

背景情况:

核糖核酸减少酶的R2亚单元对于DNA合成至关重要.
通过R2Fe (IV) 中心激活氧气涉及一个关键的中间体,X.
了解中间体X的电子结构对于阐明反应机制至关重要.

研究的目的:

为了确定中间X的电子结构.
为了研究Fe (IV) 在氧激活中的作用.
区分介质X的拟议结构模型.

主要方法:

开发一个快速结灭磁性圆形二元化 (RFQ-MCD) 协议.
收集R2 (Y122/Y356F) 的双变异体的低温RFQ-MCD数据.
电子转换和C0/D0比率的分析.

主要成果:

观察到X中间体至少有10个电子转换,与其已知的吸收频段不同.
分类过渡到Fe (((IV) 连接体场,旋转禁区和电荷转移区域.
支持显著的Fe (IV) 特性,并提供了数据来区分 bis-mu-oxo 和 mu-oxo 桥梁结构.

结论:

通过RFQ-MCD阐明中间X的电子结构.
结果强烈支持在偏磁中心内的Fe (IV) 特性.
这项研究提供了对R2中集群形成和氧气激活的分子机制的关键见解.

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