単一のリボソームによるトランスレーションに続いて,コドン1個ずつ,コドン1個ずつ
Jin-Der Wen1, Laura Lancaster, Courtney Hodges
1Department of Chemistry, University of California, Berkeley, California 94720, USA.
Nature
|March 11, 2008
まとめ
リボソーム翻訳は,連続的な動きと一時停止サイクルを伴う. mRNAの二次構造は,パウスの持続時間に影響を与え,全体的な翻訳速度に影響を与えます.
科学分野:
- 分子生物学は分子生物学である.
- バイオフィジックス 生物物理学
- 遺伝学 遺伝学とは
背景:
- タンパク質合成のダイナミクスを理解することは,分子生物学にとって極めて重要です.
- リボソームの機能とその調節は,遺伝子発現の鍵である.
研究 の 目的:
- リボソーム翻訳のステップ・バイ・ステップメカニズムを調査する.
- 翻訳ダイナミクスにおけるmRNA二次構造の役割を決定する.
主な方法:
- 単一のメッセンジャーRNA (mRNA) ヘアピンを翻訳する個々のリボソームを追跡するために光学ピンチを使用しました.
- 翻訳中の休止期間と転位時間を分析した.
主要な成果:
- 翻訳は連続した転位と一時停止サイクルを経て進行することを明らかにした.
- 各パウスのうち,少なくとも2つのレート決定プロセスを特定しました.
- 各三塩基転位イベント内に3つのサブステップを発見した.
- mRNAの二次構造が,転位時間ではなく,一時停止の長さに影響することを示した.
結論:
- 転位とRNA解離は,密接に結びついているリボソーム機能である.
- mRNAの二次構造は,休憩期間を変えることで翻訳速度を調節する.
関連する概念動画
02:07Improving Translational Accuracy
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...
02:07Improving Translational Accuracy
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...
02:33Initiation 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...
02:33Initiation 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...
01:31Translation
Lesson: Translation
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
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
01:31Translation
Lesson: Translation
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
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