相关实验视频
Updated: May 25, 2025

10:24
Xenopus laevis as a Model to Identify Translation Impairment
Published on: September 27, 2015
10.7K
在大肠杆菌中体内翻译的机制建模可靠地识别了适应良好的和优化的RNA序列
Jan Spindler1, Christina Giakissiklis1, Catharina Stierle1
1Institute of Biochemical Engineering, University of Stuttgart, Stuttgart 70569, Germany.
ACS synthetic biology
|February 27, 2025
概括
这项研究引入了翻译延长的新模型,揭示了除了编码子使用之外的因素对大肠杆菌的基因表达效率有重大影响. 该模型预测异质基因的翻译率降低,突出显示了改善蛋白质生产的区域.
科学领域:
- 分子生物学分子生物学
- 系统生物学 系统生物学
- 生物信息学是一种生物信息学.
背景情况:
- 优化基因表达通常侧重于密码子使用和tRNA偏好,但仅仅这些就会导致低于最佳的蛋白质生产.
- 翻译延长是一个复杂的过程,受mRNA序列,核糖体动力学和新生的多性质的影响.
研究的目的:
- 开发一个全面的翻译延长机制模型,包括tRNA竞争,Shine-Dalgarno相互作用和电荷效应.
- 提供对影响大肠杆菌翻译效率的因素的整体观点,并预测对异质基因表达的影响.
主要方法:
- 开发了一种机械模型,将tRNA在核糖体A位点的竞争,内部Shine-Dalgarno序列相互作用,以及带正电荷的贴片的影响整合在一起.
- 模拟大肠杆菌的翻译延长率,考虑生长速度的变化,并将内源序列与Saccharomyces cerevisiae的异构序列进行比较.
主要成果:
- 该模型捕捉了依赖于生长率的转化速率 (22-25%) 在大肠杆菌的变化.
- 内生大肠杆菌序列适应了高效的翻译,特别是在高度表达的基因中.
- 与大肠杆菌对应物相比,异质酵母序列预计具有显著较低的延长率 (14-70%).
结论:
- 翻译延长受编码子使用之外的多个因素的影响,包括tRNA竞争和性质.
- 该模型确定了翻译效率的关键决定因素,并建议了蛋白质工程和优化异质基因表达的策略.
- 带正电荷的氨基酸可以显著降低延长率,为序列优化提供特定的目标.
相关概念视频
Improving Translational Accuracy
8.5K
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...
8.5K
Initiation of Translation
30.3K
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...
30.3K
Translation
14.4K
Translation is the process of synthesizing proteins from the genetic information carried by messenger RNA (mRNA). Following transcription, it constitutes the final step in the expression of genes. This process is carried out by ribosomes, complexes of protein and specialized RNA molecules. Ribosomes, transfer RNA (tRNA), and other proteins produce a chain of amino acids—the polypeptide—as the end product of translation.
Translation Produces the Building Blocks of Life
Proteins are...
Translation Produces the Building Blocks of Life
Proteins are...
14.4K
Leaky Scanning
5.1K
During most eukaryotic translation processes, the small 40S ribosome subunit scans an mRNA from its 5' end until it encounters the first start AUG codon. The large 60S ribosomal subunit then joins the smaller one to initiate protein synthesis. The location of the translation initiation is largely determined by the nucleotides near the start codon as there may be multiple translation initiation sites present on the mRNA. Marilyn Kozak discovered that the sequence RCCAUGG (where R...
5.1K
Termination of Translation
24.7K
The large ribosomal subunit has several important structures essential to translation. These include the peptidyl transferase center (PTC) - which is the site where the peptide bond is formed - and a large, internal, water-filled tube through which the nascent polypeptide moves. This latter structure is called the Peptide Exit Tunnel, and it begins at the PTC and spans the body of the large ribosomal subunit. During translation, as the nascent polypeptide chain is synthesized, it passes through...
24.7K
Regulation of Expression Occurs at Multiple Steps
22.4K
Gene expression can be regulated at almost every step from gene to protein. Transcription is the step that is most commonly regulated. This involves the binding of proteins to short regulatory sequences on the DNA. This association can either promote or inhibit the transcription of a gene associated with the respective sequence.
Transcription results in the generation of precursor (pre-mRNA) that consists of both exons and introns, which needs further processing before being translated to a...
Transcription results in the generation of precursor (pre-mRNA) that consists of both exons and introns, which needs further processing before being translated to a...
22.4K

