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核糖体对mRNA盖的加载是由eIF4G和eIF4E之间的构造性合驱动的
John D Gross1, Nathan J Moerke, Tobias von der Haar
1Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.
Cell
|December 17, 2003
概括
细胞启动因子4G (eIF4G) 结合eIF4E和mRNA盖,形成一个分子手. 这种结构增强了翻译启动,对细胞生长至关重要.
科学领域:
- 分子生物学分子生物学
- 结构生物学 结构生物学
- 基因表达规范 基因表达规范
背景情况:
- 细胞启动因子4G (eIF4G) 是翻译启动的核心,控制基因表达.
- eIF4G与eIF3和eIF4E/cap-mRNA复合体相互作用,以促进核糖体对mRNA的加载.
- 卡普依赖翻译是蛋白质合成的关键过程.
研究的目的:
- 为了确定酵母eIF4E/cap和eIF4G (393-490) 的片段之间的复合物的溶液结构.
- 阐明eIF4G和eIF4E相互作用以调节翻译启动的机制.
主要方法:
- 对eIF4E/cap和eIF4G (393-490) 复合体的解决方案结构的确定.
- 对结合两种蛋白质的结构后果的分析.
主要成果:
- 将eIF4G (393-490) 绑定到eIF4E/cap上会诱导一个合折叠过渡.
- 形成了一个稳定的"分子手",eIF4G (393-490) 在eIF4E的N端周围形成螺旋环.
- 这种共同折叠在全质上增强了eIF4E与mRNA盖的关联.
结论:
- eIF4G-eIF4E相互作用和由此产生的结构对于最佳的细胞生长和多元体分布至关重要.
- 稳定的信使核糖蛋白 (mRNP) 复合体促进了多轮核糖体负载,影响了蛋白质合成速率.
相关概念视频
Nuclear Export of mRNA
Before mRNAs are exported to the cytoplasm, it is crucial to check each mRNA for structural and functional integrity. Eukaryotic cells use several different mechanisms, collectively known as mRNA surveillance, to look for irregularities in mRNAs. Irregular or aberrant mRNA are rapidly degraded by various enzymes. If a defective mRNA escapes the surveillance, it would be translated into a protein which would either be non-functional or not function properly. One of the primary irregularities in...
Initiation of Translation
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...
Regulated mRNA Transport
In eukaryotes, transcription and translation are compartmentalized; an mRNA is first synthesized in the nucleus and then selectively transported to the cytoplasm for protein synthesis. Before transport, a pre-mRNA undergoes several steps of post-transcriptional modifications including splicing, 5' capping, and the addition of a poly-adenine tail. Various proteins bind to the pre-mRNA during these modifications. The mRNA transport takes place with the help of multiple proteins playing specific...
Nuclear Export of mRNA
Before mRNAs are exported to the cytoplasm, it is crucial to check each mRNA for structural and functional integrity. Eukaryotic cells use several different mechanisms, collectively known as mRNA surveillance, to look for irregularities in mRNAs. Irregular or aberrant mRNA are rapidly degraded by various enzymes. If a defective mRNA escapes the surveillance, it would be translated into a protein which would either be non-functional or not function properly. One of the primary irregularities in...
Initiation of Translation
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...
Regulated mRNA Transport
In eukaryotes, transcription and translation are compartmentalized; an mRNA is first synthesized in the nucleus and then selectively transported to the cytoplasm for protein synthesis. Before transport, a pre-mRNA undergoes several steps of post-transcriptional modifications including splicing, 5' capping, and the addition of a poly-adenine tail. Various proteins bind to the pre-mRNA during these modifications. The mRNA transport takes place with the help of multiple proteins playing specific...

