[肌红蛋白,细胞染色体b5]接口的静电重新设计,以创建一个明确的对接复合体,具有快速的蛋白间电子转移
Peng Xiong1, Judith M Nocek, Amanda K K Griffin
1Northwestern University, Department of Chemistry, 2145 Sheridan Road, Evanston, Illinois 60208, USA.
Journal of the American Chemical Society
|May 8, 2009
概括
研究人员修改了肌球蛋白 (Mb),以改变其与细胞染色体b5 (cyt b5) 的相互作用. 突变使结合和电子转移机制从动态转变为简单的对接,增强反应性.
科学领域:
- 生物化学 生物化学
- 蛋白质工程是指蛋白质工程.
- 电子转移是指电子的转移.
背景情况:
- 细胞染色体b5 (cyt b5) 是一种电子载体,可降低甲基血球蛋白 (met-Mb) 和甲基血球蛋白 (met-Hb).
- 肌球蛋白 (Mb) 和cyt b5之间的相互作用发生在动态对接 (DD) 能量格局中,其中结合和反应性是不结合的.
- 这种解导致了弱结合和有限的反应性配置,阻碍了高效的电子转移 (ET).
研究的目的:
- 重新设计Mb的表面,以促进从动态对接 (DD) 切换到简单的对接 (SD) 能源景观.
- 实现一种结合和反应的情景,从而产生明确的反应结合配置.
- 为了提高Mb和cytb5.5之间的电子转移效率.
主要方法:
- 创建了一个三重突变的肌球蛋白 (Mb(+6)) 具有特定的电荷逆转 (D44K/D60K/E85K) 在它的表面.
- 在Mb突变体中用Zn-deuteroporphyrin替换了原生血红蛋白.
- 监控的细胞b5结合和电子转移 (ET) 火 (3)ZnMb(+6) 三重状态.
主要成果:
- 三重突变的Mb(+6) 将cyt b5定向到邻近血红细胞的特定表面区域.
- 形成了一个明确的,稳定的结构,支持高效的ET途径.
- 关联速率常数 (K ((a)) 和ET速率常数 (k ((et)) 增加了大约200倍,表明合结合和反应性.
- 实现了高ET速率常数 (k(et) = 10^6 s^-1) 与缓慢的交换动力学 (k(off) << k(et)).
结论:
- 设计的Mb(+6) 突变物成功地将与cyt b5的相互作用从动态对接 (DD) 转换为简单的对接 (SD) 能量景观.
- 这些突变有效地合了结合和电子转移,显著提高了ET的效率.
- 这项研究证明了重新设计蛋白质-蛋白质相互作用以控制结合和反应性的成功策略.
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