在子头 ribozyme 中探测一般酸催化
Jason M Thomas1, David M Perrin
1Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, B.C., Canada, V6T 1Z1.
Journal of the American Chemical Society
|January 22, 2009
概括
双价金属 (M(2+)) 和一个特定的 ribozyme 组对于头 ribozyme 一般酸催化是至关重要的. 这项研究澄清了它们的作用,表明M2+) -辅因子协调降低了G8 2'-OH pKa).
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 酶学 是一种酶学.
背景情况:
- 头核酶是具有催化核的RNA酶.
- 最近的研究表明,特定的 ribozyme 组和金属离子参与了催化.
- 在头 рибо酶中双价金属 (M(2+)) 的精确催化作用尚不清楚.
研究的目的:
- 为了功能性地描述S. mansoni头 ribozyme中的一般酸催化机制.
- 阐明双价金属 (M(2+)) 在这种催化过程中作为辅助因子的作用.
- 为了研究G8 2 extquotesingle-OH ribozyme残留物对一般酸催化物的贡献.
主要方法:
- 在天然的 ribo-phosphodiester 和桥接-5 extquotesingle-phosphorothioate 基质上对头 ribozyme 分裂的比较分析.
- 在G8 2 extquotesingle-OH ribozyme残留物的位点导向突变发生.
- 替代双价金属 (M(2+)) 辅助因子.
- 放射性标记的桥梁-5 extquotesingle-phosphorothioate基质的合成.
主要成果:
- 自然基质的裂变被G8 2 extquotesingle-OH修饰和M(2+) 辅因子的存在/身份所抑制.
- 酸基质的裂变对这些修改无感.
- 在M2+) 替代和G8 2 extquotesingle-OH 修改时观察到一般酸 pK (a) 扰动.
结论:
- 两个M(2+) 辅因子和G8 2 extquotesingle-OH对于头利博酶一般酸催化是必不可少的.
- M(2+) 辅因子不会通过易斯酸相互作用稳定离开的组.
- 过渡状态M(2+) 协调G8 2 extquotesingle-OH可能会降低其pK(a),增强对离开组的质子转移.
相关概念视频
Ribozymes
The term ribozyme is used for RNA that can act as an enzyme. Ribozymes are mainly found in selected viruses, bacteria, plant organelles, and lower eukaryotes. Ribozymes were first discovered in 1982 when Tom Cech’s laboratory observed Group I introns acting as enzymes. This was shortly followed by the discovery of another ribozyme, Ribonulcease P, by Sid Altman’s laboratory. Both Cech and Altman received the Nobel Prize in chemistry in 1989 for their work on ribozymes.
Ribozymes can be...
Ribozymes can be...
Ribozymes
The term ribozyme is used for RNA that can act as an enzyme. Ribozymes are mainly found in selected viruses, bacteria, plant organelles, and lower eukaryotes. Ribozymes were first discovered in 1982 when Tom Cech’s laboratory observed Group I introns acting as enzymes. This was shortly followed by the discovery of another ribozyme, Ribonulcease P, by Sid Altman’s laboratory. Both Cech and Altman received the Nobel Prize in chemistry in 1989 for their work on ribozymes.
Ribozymes can be...
Ribozymes can be...
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