设计酶:将tRNA特异性编程为柔性酶
Krishna Ramaswamy1, Hirohide Saito, Hiroshi Murakami
1Departments of Chemistry and Biological Sciences, University at Buffalo, State University of New York, Buffalo, NY 14260-3000, USA.
Journal of the American Chemical Society
|September 16, 2004
概括
研究人员设计了一种新的人工酶,Fx10,专门附加氨基酸转移RNA (tRNA). 这种定制的催化剂可以精确地创建非天然的氨基酸tRNA,用于先进的生物技术.
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 合成生物学 合成生物学
背景情况:
- 像Fx3这样的人工 ribozymes 可以与氨及其衍生物一起氨基酸转移RNA (tRNA).
- 一般的 ribozymes 缺乏特异性,限制了它们在精确合成中的应用.
研究的目的:
- 为了设计一种具有增强tRNA特异性的通用 ribozyme (Fx3).
- 创建一个可定制的催化系统,用于生成非自然氨基酸tRNAs.
主要方法:
- 将一个tRNA特异序列 (TSS) 附加到Fx3 ribozyme的3'-end.
- 设计TSS以补充目标tRNA的受体干.
- 描述修改后的 ribozyme (Fx10) 和相关/非相关的 tRNA 之间的相互作用.
主要成果:
- 新的设计核糖酶Fx10特别识别并氨基酸化其同类tRNA.
- Fx10利用由TSS入侵tRNA受体干形成的10个基对相互作用.
- Fx10表现出高特异性,有效地对非同源tRNA进行歧视.
结论:
- 开发了一种简单的策略,将tRNA特异性传递给人工 ribozymes.
- Fx10作为一种可编程,定制的催化剂,用于产生特定的非自然氨基酸tRNAs.
- 这种方法促进了生物技术应用的多种非天然氨基酸tRNA的生成.
相关概念视频
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Base complementarity between the three base pairs of mRNA codon and the tRNA anticodon is not a failsafe mechanism. Inaccuracies can range from a single mismatch to no correct base pairing at all. The free energy difference between the correct and nearly correct base pairs can be as small as 3 kcal/ mol. With complementarity being the only proofreading step, the estimated error frequency would be one wrong amino acid in every 100 amino acids incorporated. However, error frequencies observed in...
02:36Transfer RNA Synthesis
One of the unique features of tRNA is the presence of modified bases. In some tRNAs, modified bases account for nearly 20% of the total bases in the molecule. Altogether, these unusual bases protect the tRNA from enzymatic degradation by RNases.
Each of these chemical modifications is carried by a specific enzyme, post-transcription. All of these enzymes have unique base and site-specificity. Methylation, the most common chemical modification, is carried by at least nine different enzymes, with...
Each of these chemical modifications is carried by a specific enzyme, post-transcription. All of these enzymes have unique base and site-specificity. Methylation, the most common chemical modification, is carried by at least nine different enzymes, with...
02:26tRNA Activation
Aminoacyl-tRNA synthetases are present in both eukaryotes and bacteria. Though eukaryotes have 20 different aminoacyl-tRNA synthetases to couple to 20 amino acids, many bacteria do not have genes for all of these aminoacyl-tRNA synthetases. Despite this, they still use all 20 amino acids to synthesize their proteins. For instance, some bacteria do not have the gene encoding the enzyme that couples glutamine with its partner tRNA. In these organisms, one enzyme adds glutamic acid to all of the...