タイロシル-tRNA合成酵素のスプライシング因子の構造は,グループIのイントロンRNAに結合している
Paul J Paukstelis1, Jui-Hui Chen, Elaine Chase
1Institute for Cellular and Molecular Biology, Department of Chemistry and Biochemistry, and Section of Molecular Genetics and Microbiology, School of Biological Sciences, University of Texas at Austin, Austin, Texas 78712, USA.
Nature
|January 4, 2008
まとめ
タンパク質はRNAのスプライシングを支援するために進化し,RNA世界からRNP世界へと移行した. 新しい結晶構造は,タンパク質 (CYT-18) がグループIイントロンを結合し,そのスプライシングと進化を助ける方法を示しています.
科学分野:
- 進化生物学の進化生物学について
- 構造生物学 構造生物学とは
- 分子生物学は分子生物学である.
背景:
- "RNA世界"仮説は,RNAが最初は遺伝的および触媒的機能の両方を果たしていたことを示唆しています.
- 現代生物学では,リボ酵素とタンパク質-RNA複合体 (RNP酵素) が特徴であり,RNAからタンパク質の優位性への移行を示している.
- グループIのイントロン,RNA触媒は,しばしばタンパク質によって安定したRNP酵素として機能する.
研究 の 目的:
- タンパク質媒介によるグループIイントロンスプライシングの構造的基礎を解明する.
- タンパク質のRNA触媒への進化的適応を理解する.
- RNA世界からRNP世界への移行に関する洞察を提供するために.
主な方法:
- 断片化されたスプライシング活性タンパク質 (CYT-18) に結合するグループIイントロンリボ酵素の4.5-Å共結晶構造を決定した.
- イントロンRNAとホモジメールタンパク質の構造的相互作用を分析した.
- CYT-18のイントロン結合表面を,スプライシングしない細菌のチロシル-tRNA合成酵素と比較した.
主要な成果:
- グループIイントロンは,同位体タンパク質CYT-18の両方のサブユニットに結合する.
- CYT-18の新しいRNA結合表面は,イントロンの触媒核を安定させる.
- 小さな挿入を含むCYT-18の適応は,グループIのイントロン結合とスプライシングを容易にし,スプライシングしないTyrRSと区別する.
結論:
- CYT-18の構造は,グループIのイントロンスプライシングを促進するメカニズムを明らかにしています.
- 発見は,RNAスプライシングのためのタンパク質の多段階の進化的適応を示しています.
- この研究は,生命の初期にタンパク質が徐々にRNA機能を置き換えた方法について,構造的な視点を提供している.
関連する概念動画
RNA Splicing
Splicing is the process by which eukaryotic RNA is edited before its translation into protein. The RNA strand transcribed from eukaryotic DNA is called the primary transcript. The primary transcripts that become mRNAs are called precursor messenger RNAs (pre-mRNAs). Eukaryotic pre-mRNA contains alternating sequences of exons and introns. Exons are nucleotide sequences that code for proteins, whereas introns are the non-coding regions. In RNA splicing, introns are removed and exons are bonded...
RNA Splicing
Splicing is the process by which eukaryotic RNA is edited before its translation into protein. The RNA strand transcribed from eukaryotic DNA is called the primary transcript. The primary transcripts that become mRNAs are called precursor messenger RNAs (pre-mRNAs). Eukaryotic pre-mRNA contains alternating sequences of exons and introns. Exons are nucleotide sequences that code for proteins, whereas introns are the non-coding regions. In RNA splicing, introns are removed and exons are bonded...
Transfer 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...
Alternative RNA Splicing
Alternative RNA splicing is the regulated splicing of exons and introns to produce different mature mRNAs from a single pre-mRNA. Unlike in constitutive splicing where a single gene produces a single type of mRNA, alternative splicing allows an organism to produce multiple proteins from a single gene and plays an important role in protein diversity.
There are five types of alternative RNA splicing that vary in the ways the pre-mRNA segments are removed or retained in the mature mRNA. The first...
There are five types of alternative RNA splicing that vary in the ways the pre-mRNA segments are removed or retained in the mature mRNA. The first...
Alternative RNA Splicing
Alternative RNA splicing is the regulated splicing of exons and introns to produce different mature mRNAs from a single pre-mRNA. Unlike in constitutive splicing where a single gene produces a single type of mRNA, alternative splicing allows an organism to produce multiple proteins from a single gene and plays an important role in protein diversity.
There are five types of alternative RNA splicing that vary in the ways the pre-mRNA segments are removed or retained in the mature mRNA. The first...
There are five types of alternative RNA splicing that vary in the ways the pre-mRNA segments are removed or retained in the mature mRNA. The first...
Transfer 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...


