双重金属离子与催化RNA中的核基的内球协调
Xin Liu1, Yu Chen1, Carol A Fierke1
1Departments of Chemistry and ‡Biological Chemistry, University of Michigan , Ann Arbor, Michigan 48109, United States.
Journal of the American Chemical Society
|November 9, 2017
概括
这项研究揭示了核酶P中的特定RNA基如何与金属离子相互作用以进行催化. 经过修改的RNA显示活性降低,金属救援实验证实了关键尿素基的直接协调.
科学领域:
- 生物化学
- 分子生物学
- RNA催化剂
背景情况:
- 了解金属离子和核基的作用对于RNA催化是至关重要的.
- 细菌核糖酶P (RNase P) 是参与tRNA处理的关键RNA酶.
- 之前的研究表明,在螺旋P4坐标金属离子中保留了尿素和瓜诺辛.
研究的目的:
- 在RNase P中生物化学探测金属离子与保存核基相互作用的功能.
- 研究尿素 (U51) 和瓜诺辛 (G379) 在RNase P的P4螺旋中的特定作用.
主要方法:
- 在Bacillus subtilis P RNA中使用单原子和基底核酸替代.
- 修改保存的U51为4-氨酸,4-脱氧氨酸和低类型.
- 修改后保存的G378/379变成了2-阿米诺,N7-迪阿扎瓜诺和6-瓜诺.
主要成果:
- U51的功能组修改减少了RNase P催化剂的16至23倍.
- 部分由Cd (II) 或Mn (II) 离子挽救,表明内球协调.
- G379的修改显示了适度的活动减少, 暗示外层金属离子协调.
结论:
- 提供了RNase P的P4螺旋中具有重要催化作用的金属离子相互作用的生化证据.
- 证明膨胀的尿素 (U51) 通过内部球相互作用直接协调至少一个催化金属离子.
- 突出了单原子和基基替换在大型RNA中探测核基功能的实用性.
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