通过质子管理调节激进中继残留物 拯救蛋白质电子跳跃
Estella F Yee1, Boris Dzikovski1,2, Brian R Crane1
1Department of Chemistry and Chemical Biology , Cornell University , Ithaca , New York 14853 , United States.
Journal of the American Chemical Society
|October 12, 2019
概括
蛋白质中的氨酸基因通常由于脱质. 添加一个键供体到铁基显著增加电子转移率,使蛋白质功能高效.
科学领域:
- 生物化学
- 蛋白质基化学
- 电子转移
背景情况:
- 短暂的氨酸和氨酸基对于各种蛋白质的电子转移至关重要.
- 不完全了解Tyr和Trp基的功能互换性和反应性因素.
- 细胞染色体c过氧化酶 (CcP) 使用Trp191基来氧化细胞染色体c (Cc),但Tyr191替代物尽管形成稳定基,但却不活跃.
研究的目的:
- 通过修改其环境来研究CcP Tyr191的氧化还原特性.
- 了解为什么Tyr191与Trp191相比在Cc氧化中不活跃.
- 探索增强蛋白质中Tyr基活性的策略.
主要方法:
- 非自然氨基酸替代 (甲酸).
- 频谱技术 (ESR,ESEEM) 的使用.
- 结晶学和依赖pH的动力学.
- 快速结灭ESR光谱
主要成果:
- 氨酸替代剂对ET率产生了轻微的影响.
- 在Tyr191引入键供体 (His232或Glu232) 时,ET率增加了30倍.
- 与Tyr191基的结合使其形式潜力增加了约200mV.
- Y191的不活性源于由于脱质的潜在下降,而这种下降是由结合所逆转的.
结论:
- 一个能够接受和捐赠键的正确位置将提升Tyr基潜力,从而实现有效的电子转移.
- 这种机制解释了Tyr191在CcP中的不活性,并对其他蛋白质如PSII和RNR产生影响.
- 具有特定结相互作用的工程蛋白可以增强远程电子传输能力.
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