通过人类lysyl-tRNA合成酶对细胞修饰的tRNALys3进行氨基化的结构基础
Swapnil C Devarkar1, Christina R Budding2, Chathuri Pathirage2
1Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511, United States.
Nucleic acids research
|March 4, 2025
概括
这项研究揭示了转移RNA (tRNA) 上的特定修改对于人类lysyl-tRNA合成酶 (h-LysRS) 在蛋白质合成过程中准确地附着 lysine 是如何必不可少的. 这些发现澄清了tRNA氨基化及其与疾病的联系.
科学领域:
- 分子生物学分子生物学
- 结构生物学 结构生物学
- 生物化学 生物化学
背景情况:
- 细胞转移RNA (tRNA) 具有众多的转录后修饰,但它们的功能意义在很大程度上未被描述.
- 在甲基动物中复杂的tRNA氨基化机制尚未完全理解.
研究的目的:
- 阐明通过人类lysyl-tRNA合成酶 (h-LysRS) 识别和氨基化改性tRNALys3的机制基础.
- 研究特定tRNA修饰在h-LysRS.的催化过程和调节中的作用.
主要方法:
- 使用高分辨率冷电子显微镜 (cryo-EM) 来确定h-LysRS-tRNALys3复合物的结构.
- 结构分析的重点是修改后的tRNALys3和h-LysRS之间的相互作用,包括反子循环,T-,变量-和D-循环.
- 研究了多tRNA合成酶复合物衍生的对h-LysRS活性的影响.
主要成果:
- 关键的tRNA修改,mk5s2U (S34) 和ms2t6A (R37) 在抗环中,对于h-LysRS的识别至关重要.
- 在tRNALys3的T-,变量-和D-循环中的修改对于h-LysRS.的甲状动物特异性N-终端域的正确定向至关重要.
- 氨基化过程是结构上有序的,3'-CCA末端对接发生在中间体形成和酸盐释放后.
- 通过结合多tRNA合成酶复合体中的,通过稳定3'-CCA末端对接形状,全osterically提高h-LysRS的催化效率.
结论:
- 特定的tRNA修改是h-LysRS. 精确识别和高效氨基化的一个组成部分.
- 结构性见解提供了对甲基动物中tRNA氨基化机制的理解.
- 这些发现对理解蛋白质合成,tRNA生物学以及与氨基酸化缺陷相关的疾病有影响.
更多相关视频
07:26Site Specific Lysine Acetylation of Histones for Nucleosome Reconstitution using Genetic Code Expansion in Escherichia coli
Published on: December 26, 2020
3.9K
11:19Isolation of Translating Ribosomes Containing Peptidyl-tRNAs for Functional and Structural Analyses
Published on: February 25, 2011
19.8K
相关概念视频
02:26tRNA Activation
18.8K
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...
18.8K
02:36Transfer RNA Synthesis
11.8K
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...
11.8K
01:19RNA Structure
4.6K
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...
4.6K
02:07Improving 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
02:53Ribosomal RNA Synthesis
13.1K
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,...
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,...
13.1K
02:33Initiation 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