関連する実験動画
Updated: Jul 26, 2026

08:07
Single Molecule Fluorescence Energy Transfer Study of Ribosome Protein Synthesis
Published on: July 6, 2021
信号認識粒子受容体は,リボソームのトランスロコン結合部位を暴露する
Mario Halic1, Marco Gartmann, Oliver Schlenker
1Institute of Biochemistry, Charité, University Medical School Berlin, Monbijoustrasse 2, 10117 Berlin, Germany.
まとめ
信号認識粒子 (SRP) 受容体はSRPとリボソームを結合し,タンパク質標的化のための重要な部位を膜に露出します. この相互作用は,タンパク質の転位の間に延長停止を維持します.
科学分野:
- 分子生物学は分子生物学である.
- 構造生物学 構造生物学とは
- 細胞生物学 細胞生物学
背景:
- 分泌および膜タンパク質は,細胞の宛先に到達するために特定のターゲットメカニズムを必要とします.
- 信号認識粒子 (SRP) 経路は,これらのタンパク質をエンドプラズマの網膜膜に誘導するために極めて重要です.
- SRP受容体は,SRP結合リボソームとタンパク質転位機構 (トランスロコン) の間の相互作用を促進します.
研究 の 目的:
- タンパク質ターゲティング中のSRP-SRP受容体相互作用の構造的基礎を解明する.
- 関連する分子再配置を理解するために,高解像度で"ドッキング複合体"を視覚化します.
- SRP受容体がSRP-リボソーム複合体の構造にどのように影響するかを決定する.
主な方法:
- 複合体の構造を決定するために,冷凍電子顕微鏡 (cryo-EM) が採用されました.
- ドッキング複合体の8アングストームの解像度構造が得られました.
- 複合体は,信号認識粒子 (SRP) に結合した80SリボソームとSRP受容体で構成されています.
主要な成果:
- 構造は,ドッキング複合体内のSRP受容体,SRP,およびリボソームの正確な配置を明らかにします.
- SRP受容体との相互作用により,SRPのS領域の構造変化が誘発された.
- トランスロコンのリボソーム結合部位 (L23e/L35部位) が受容体結合時に暴露された.
- Aluドメイン媒介の延長停止が持続することが観察されました.
結論:
- SRP受容体は,SRP-リボソーム複合体の再構成において重要な役割を果たし,タンパク質の転位を促進します.
- L23e/L35部位の露出は,SRP受容体が媒介する重要なステップであり,リボソームをトランスロコンへの転送のために準備します.
- この研究は,タンパク質ターゲティングと膜挿入の基本的なプロセスに関する原子レベルの洞察を提供します.
関連する概念動画
Ribosome Profiling
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 helps...
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 helps...
Directing Proteins to the Rough Endoplasmic Reticulum
The organelle-specific signaling sequences direct proteins synthesized in the cytosol to their final destination like ER, mitochondria, peroxisomes, etc. Some of the proteins directed to ER are then trafficked via vesicles to other organelles within the cell or the extracellular environment through the Golgi complex. For example, the rough ER synthesizes soluble proteins for transportation to the lysosomes or secretion out of the cell. It can also synthesize transmembrane proteins that can...
Cotranslational Protein Translocation
Translocation of proteins across membranes is an ancient process that occurs even in bacteria and archaebacteria. In fact, the components of the translocation machinery are still conserved between prokaryotes and eukaryotes.
Sec61 channel partners for cotranslational translocation
During cotranslational translocation, the Sec61 channel partners with the signal recognition particle (SRP), the signal recognition particle receptor (SR), and the ribosomes to transport the nascent polypeptide chain...
Sec61 channel partners for cotranslational translocation
During cotranslational translocation, the Sec61 channel partners with the signal recognition particle (SRP), the signal recognition particle receptor (SR), and the ribosomes to transport the nascent polypeptide chain...
Insertion of Single-pass Transmembrane Proteins in the RER
Integral membrane proteins are proteins adhered to the lipid bilayer of a cell organelle or membrane. They can be of two types: transmembrane integral proteins that span the lipid bilayer and monotopic proteins that are attached to either side of the membrane but do not pass through it.
Integral transmembrane proteins possess transmembrane and extra membrane domains. The transmembrane domains are primarily made of 20-25 hydrophobic amino acids arranged in a helical secondary confirmation. These...
Integral transmembrane proteins possess transmembrane and extra membrane domains. The transmembrane domains are primarily made of 20-25 hydrophobic amino acids arranged in a helical secondary confirmation. These...
Post-translational Translocation of Proteins to the RER
A sizable fraction of proteins destined for ER are first synthesized in the cell cytosol and then transported across the ER membrane–a process called post-translational translocation. Similar to cotranslationally translocated proteins, these proteins also use the Sec translocon complex to enter the ER lumen.
Targeting proteins to the ER
Hsp40 and Hsp70 chaperone molecules bind the translated proteins in the cytosol to prevent their folding. The chaperone binding helps to keep the signal...
Targeting proteins to the ER
Hsp40 and Hsp70 chaperone molecules bind the translated proteins in the cytosol to prevent their folding. The chaperone binding helps to keep the signal...
Protein Translocation Machinery on the ER Membrane
The translocon complex situated on the ER membrane is the main gateway for the protein secretory pathway. It facilitates the transport of nascent peptides into the ER lumen and their insertion into the ER membrane.
Sec61 protein conducting channel
In eukaryotes, the translocon complex comprises a core heterotrimeric translocator channel called the Sec61 complex. This channel includes three transmembrane proteins, Sec61α, Sec61β, and Sec61γ, and is the largest subunit of the translocon complex.
Sec61 protein conducting channel
In eukaryotes, the translocon complex comprises a core heterotrimeric translocator channel called the Sec61 complex. This channel includes three transmembrane proteins, Sec61α, Sec61β, and Sec61γ, and is the largest subunit of the translocon complex.

