氨基酸-tRNAs通过热力学补偿对延长因子Tu的均结合
F J LaRiviere1, A D Wolfson, O C Uhlenbeck
1Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309-0215, USA.
Science (New York, N.Y.)
|October 6, 2001
概括
延长因子Tu (EF-Tu) 显示对氨基酸tRNAs的特异性,结合不同亲和度的错基化tRNAs. 这表明了EF-Tu的存在.
科学领域:
- 分子生物学分子生物学
- 蛋白质合成 蛋白质合成
- 生物化学 生物化学
背景情况:
- 延长因子Tu (EF-Tu) 对于在蛋白质合成过程中将氨基酸转移RNA (aa-tRNA) 输送到核糖体至关重要.
- 蛋白质合成的忠实性依赖于EF-Tu.tu.精确选择a-tRNAs的精确选择.
研究的目的:
- 调查EF-Tu对正确化和不正确化tRNA的结合特异性.
- 确定EF-Tu与aa-tRNAs和错基化tRNAs相互作用的热力学基础.
主要方法:
- 对EF-Tu的结合亲和度测量,使用一组正确乙基化和异乙基化tRNA进行测量.
- 热力学分析来剖析氨基酸和tRNA体对结合的贡献.
主要成果:
- 与相似的aa-tRNA相比,EF-Tu对错误结合的tRNA具有显著更广泛的结合亲和力.
- 结合亲和力受到氨基酸侧链和tRNA体的影响,具有独立的热力学贡献.
- 某些错基化tRNA与EF-Tu结合的亲和力比它们的同类更高或更低.
结论:
- 对于氨基酸和tRNA部分,EF-Tu具有相当大的特异性.
- 观察到的差异性结合亲缘关系表明EF-Tu在通过对错误结合的tRNA进行歧视来提高翻译精度方面可能发挥作用.
相关概念视频
01:23RNA Structure
Overview
The basic structure of RNA consists of a five-carbon sugar and one of four nitrogenous bases. 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): messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). All three RNA types consist of a...
The basic structure of RNA consists of a five-carbon sugar and one of four nitrogenous bases. 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): messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). All three RNA types consist of a...
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...
01:19RNA Structure
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...
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...