一种一般的RNA封装 ribozyme 在封装交换期间保留立体化学
1Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, BC, Canada.
Journal of the American Chemical Society
|October 19, 2006
概括
这项研究表明,RNA封闭型核糖酶在反应过程中保留了立体化学物质,与其他核糖酶不同. 这表明,由于化学必要性,RNA和蛋白质封闭催化剂的共同进化路径.
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 在RNA催化过程中.
背景情况:
- рибо酶是具有催化活性的RNA分子.
- 许多已知的 ribozymes 在反应期间在中心逆转立体化学.
- RNA封闭对于mRNA稳定性和翻译至关重要.
研究的目的:
- 为了研究RNA封闭 ribozyme 反应的立体化学结果.
- 为了阐明RNA被这种 ribozyme 封闭的动力机制.
- 将催化机制与已知的基于蛋白质的封闭酶进行比较.
主要方法:
- 合成立体化学定义的RNA盖 (Rp和Sp异构体).
- 用修饰的核酸基质和放射性标记的ATP化 ribozyme.
- 封装,酸盐释放和水解的动态分析.
- 对反应产物的立体化学分析.
主要成果:
- 这种RNA-capping ribozyme在中心保留了立体化学,与反转的 ribozymes 不同.
- 覆盖Rp的基板反应,而覆盖Sp的基板则没有反应,即使是与性离子.
- 封装动力学遵循迈凯利斯-门行为,酸盐的释放独立于基质度.
- 限制和水解速度的总和等于酸盐释放率,表明早期的速度限制步骤.
结论:
- RNA-capping ribozyme 机制涉及两个反转步骤,由一个共价中间体分开.
- 这种机制类似于蛋白质封闭酶,表明由化学约束驱动的融合进化.
- 立体化学保留是区分这种 ribozyme 的封闭机制的一个关键特征.
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...
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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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Ribosome synthesis is a highly complex and coordinated process involving more than 200 assembly factors. The synthesis and processing of ribosomal components occurs not only in the nucleolus but also in the nucleoplasm and the cytoplasm of eukaryotic cells.
Ribosome biogenesis begins with the synthesis of 5S and 45S pre-rRNAs by distinct RNA polymerases. The primary transcripts are extensively processed and modified before they are bound and folded by ribosomal proteins and assembly factors,...
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