进化大肠杆菌以使用具有非正规折叠的tRNA作为遗传密码的适配器
Martin P Edelmann1, Sietse Couperus1, Emilio Rodríguez-Robles1
1Department of Biosystems Science and Engineering, Bioprocess Laboratory, ETH Zurich, 4056 Basel, Switzerland.
Nucleic acids research
|September 24, 2024
概括
研究人员通过开发一种新的遗传系统,进化了细菌以使用非正规转移RNA (tRNA). 这项研究揭示了细菌翻译机制的意想不到的灵活性,接受改变的tRNA结构.
科学领域:
- 分子生物学分子生物学
- 遗传学 遗传学 是一个
- 生物化学 生物化学
背景情况:
- 细菌转移RNAs (tRNAs) 通常采用保存的三叶草 (2D) 和L形 (3D) 结构.
- 在细菌翻译系统中对tRNA功能的结构要求尚未完全理解.
研究的目的:
- 研究引入结构非正规的tRNAs进入细菌翻译的可能性.
- 探索细菌翻译机制对改变的tRNA结构的适应性.
主要方法:
- 在大肠杆菌中开发一种基于维生素的遗传系统,将生长与tRNA活动结合起来.
- 菌株的演化利用非正规的tRNA,包括一个缺乏D臂的迷你tRNA.
- 基因和体外翻译实验,以确认迷你tRNA被翻译机器接受.
主要成果:
- 一种新型的正交胺抑制器tRNA (HisTUAC) 和它的同类氨基-tRNA合成酶 (HisS) 被设计出来.
- 进化导致了一种利用小型tRNA (缺少D臂) 的菌株,通过RNase基因 (pnp) 的突变.
- 细菌的翻译系统 (HisS,核糖体,EF-Tu) 证明了对迷你tRNA的接受.
结论:
- 细菌的翻译机制在接受tRNA结构方面表现出比以前所知的更大的灵活性.
- 基于维生素的抑制系统是开发和研究非正规tRNAs的强大工具.
- 这项工作扩大了我们对适应分子在遗传密码中的作用的理解.
更多相关视频
11:51Engineering 'Golden' Fluorescence by Selective Pressure Incorporation of Non-canonical Amino Acids and Protein Analysis by Mass Spectrometry and Fluorescence
Published on: April 27, 2018
11.9K
11:08A Facile Protocol to Generate Site-Specifically Acetylated Proteins in Escherichia Coli
Published on: December 9, 2017
7.0K
相关概念视频
Transfer RNA Synthesis
11.9K
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...
11.9K
Improving Translational Accuracy
9.4K
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...
9.4K
tRNA Activation
19.1K
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...
19.1K
Initiation of Translation
31.7K
Initiating translation is complex because it involves multiple molecules. Initiator tRNA, ribosomal subunits, and eukaryotic initiation factors (eIFs) are all required to assemble on the initiation codon of mRNA. This process consists of several steps that are mediated by different eIFs.
First, the initiator tRNA must be selected from the pool of elongator tRNAs by eukaryotic initiation factor 2 (eIF2). The initiator tRNA (Met-tRNAi) has conserved sequence elements including modified bases at...
First, the initiator tRNA must be selected from the pool of elongator tRNAs by eukaryotic initiation factor 2 (eIF2). The initiator tRNA (Met-tRNAi) has conserved sequence elements including modified bases at...
31.7K
From DNA to Protein
18.1K
The flow of genetic information in cells from DNA to mRNA to protein is described by the central dogma, which states that genes specify the sequence of mRNAs, which in turn specify the sequence of amino acids making up all proteins. The decoding of one molecule to another is performed by specific proteins and RNAs. Because the information stored in DNA is so central to cellular function, it makes intuitive sense that the cell would make mRNA copies of this information for protein synthesis...
18.1K
RNA Structure
4.7K
The basic structure of RNA consists of a string of ribonucleotides attached by phosphodiester bonds. Although most RNA is single-stranded, it can form complex secondary and tertiary structures. Such structures play essential roles in the regulation of transcription and translation.
Different Types of RNA Have the Same Basic Structure
There are three main types of ribonucleic acid (RNA) involved in protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). All three...
Different Types of RNA Have the Same Basic Structure
There are three main types of ribonucleic acid (RNA) involved in protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). All three...
4.7K
