リボソームの衝突により,バクテリアのmRNA分裂とリボソーム救済が誘発される
Kazuki Saito1, Hanna Kratzat2, Annabelle Campbell1
1Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, USA.
Nature
|March 10, 2022
まとめ
バクテリアは新しい救出因子SMRBを使って 停滞したリボソームを浄化します SmrBは停滞したリボソームでmRNAを分割し,tmRNAはリボソームを上流に救出し,タンパク質の分解を防ぐことができます.
科学分野:
- 細菌分子生物学
- タンパク質の合成と調節
- リボソームの機能と機能障害
背景:
- リボソームの救済経路は細菌の細胞恒常性にとって極めて重要です.
- 停止したリボソームと活発に変換しているリボソームを区別するメカニズムは,まだ十分に理解されていません.
- 既存の経路は問題のあるmRNAやタンパク質を標的として分解する.
研究 の 目的:
- バクテリアのリボソーム救出に関わる新しい要因を特定する.
- バクテリアが停滞したリボソームを分化させるメカニズムを解明する.
- リボソームの衝突が どのように救命経路を 引き起こすかを理解するためです
主な方法:
- エシェリキア・コーライの遺伝子スクリーニングで 新しい救出因子を発見します
- SmrBの内核酵素活性を決定する生化学的測定
- 衝突したリボソームとSmrB結合部位を視覚化するための冷凍電子顕微鏡
主要な成果:
- エンドヌクレアース活性を持つ新しい細菌救済因子のSmrBの発見
- SmrBは停滞したリボソームの前方にmRNAを分割し,tmRNA媒介による救済を容易にします.
- リボソームの衝突が SmrBの徴募と活性化のトリガとして特定されました.
- Cryo-EM構造は,衝突したリボソームに保存されたSmrB結合部位を明らかにしました.
結論:
- SmrBは,mRNAを分裂することによって,細菌のリボソームの救済に重要な役割を果たします.
- リボソームの衝突は SmrB 救出経路を活性化するための重要な信号です
- この研究は 細菌におけるリボソーム救済の保存メカニズムを明らかにした.
関連する概念動画
01:29Coordination of Gene Expression Processes in Bacteria
200
The DNA replication, transcription, and translation processes are intricately coupled in bacteria, allowing efficient gene expression and rapid protein synthesis. While this physical and functional coordination is advantageous, it introduces challenges that bacteria overcome through specific regulatory mechanisms.Coupling of Replication, Transcription, and TranslationThe coupling of replication, transcription, and translation is a hallmark of bacterial gene expression. As the replisome unwinds...
200
02:07Improving Translational Accuracy
11.9K
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...
11.9K
02:24Ribosome Profiling
3.7K
Ribosome profiling or ribo-sequencing is a deep sequencing technique that produces a snapshot of active translation in a cell. It selectively sequences the mRNAs protected by ribosomes to get an insight into a cell’s translation landscape at any given point in time.
Applications of ribosome profiling
Ribosome profiling has many applications, including in vivo monitoring of translation inside a particular organ or tissue type and quantifying new protein synthesis levels.
The technique...
Applications of ribosome profiling
Ribosome profiling has many applications, including in vivo monitoring of translation inside a particular organ or tissue type and quantifying new protein synthesis levels.
The technique...
3.7K
01:26Bacterial Protein Maturation
123
Bacterial protein maturation is a tightly regulated process that ensures newly synthesized polypeptides achieve correct functional conformations. This maturation involves a series of modifications, folding events, and quality control steps, often assisted by specialized chaperone proteins.N-Terminal ModificationsThe maturation of bacterial polypeptides begins cotranslationally as the polypeptide exits the ribosome. The first amino acid, N-formylmethionine (fMet), is typically modified at the...
123
01:29Translation in Prokaryotes
310
Prokaryote translation is a complex, highly coordinated process that converts genetic information from mRNA into functional proteins. It involves three stages: initiation, elongation, and termination, each facilitated by specific molecular components.Initiation of TranslationThe process begins with the assembly of the ribosomal subunits and initiation factors on the mRNA. In bacteria, the 30S ribosomal subunit recognizes the Shine-Dalgarno sequence in the mRNA, a conserved region upstream of...
310
01:23Types of RNA
68.5K
Overview
Three main types of RNA are involved in protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). These RNAs perform diverse functions and can be broadly classified as protein-coding or non-coding RNA. Non-coding RNAs play important roles in the regulation of gene expression in response to developmental and environmental changes. Non-coding RNAs in prokaryotes can be manipulated to develop more effective antibacterial drugs for human or animal use.
RNA...
Three main types of RNA are involved in protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). These RNAs perform diverse functions and can be broadly classified as protein-coding or non-coding RNA. Non-coding RNAs play important roles in the regulation of gene expression in response to developmental and environmental changes. Non-coding RNAs in prokaryotes can be manipulated to develop more effective antibacterial drugs for human or animal use.
RNA...
68.5K