二元原子连接体与尼特罗福林结合的超快动态 4
Abdelkrim Benabbas1, Xiong Ye, Minoru Kubo
1Department of Physics and Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, Massachusetts 02115, USA.
Journal of the American Chemical Society
|February 4, 2010
概括
尼托福林4 (NP4) 结合氧化物 (NO) 在其铁状和铁状状态不同. 铁性NP4表现出快速的NO重结,而铁性NP4则表现出pH依赖的NO释放,这对其生物功能至关重要.
科学领域:
- 生物化学 生物化学
- 蛋白质动力学 蛋白质动力学
- 氧化信号传输系统
背景情况:
- 酸4 (NP4) 是一种被称为储存和释放氧化 (NO) 的血红蛋白.
- 它的功能依赖于对pH敏感的结构变化,影响NO的结合和释放.
- 蛋白质利用铁态在低pH时紧密结合NO,在高pH时释放.
研究的目的:
- 为了研究NO和一氧化碳 (CO) 到NP4.4的重结动力学.
- 检查铁的氧化状态和环境pH对这些动力学的影响.
- 阐明NP4的NO储存和释放功能背后的机制.
主要方法:
- 超快速运动光谱学.
- 对NO和CO重新结合到NP4的时间解析研究.
- 分析蛋白质构成变化作为pH值的函数.
主要成果:
- 双NO与铁NP4的重组是快速的 (~7 ps) 和pH独立的,这表明铁状态对NO释放的功能实用性有限.
- 铁性NP4NO表现出双相NO重结,其相振幅较慢,随着pH值 (5到8) 的显着增加.
- 来自铁性NP4的NO的脱离率从pH5增加到8,与蛋白质"开放"形状相关.
结论:
- 由于快速,不依赖pH的重新结合,NP4的铁状状态无法优化NO释放.
- 铁态的NO释放是由pH值依赖的形状变化调节的,特别是囊的开放.
- NP4释放NO的能力与"开放"状态的人口和相关的逃逸动态直接相关,突出其在NO输送中的作用.
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