バクテリアのSecYE構造から推論されたSec機械のコンフォームトランジション
Tomoya Tsukazaki1, Hiroyuki Mori, Shuya Fukai
1Department of Biological Information, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama-shi, Kanagawa 226-8501, Japan.
Nature
|October 17, 2008
まとめ
セックスのトランスロコン.
科学分野:
- 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.
- 蛋白質の転位によるタンパク質転位です.
背景:
- タンパク質の30%以上は膜統合または分泌されている.
- Secトランスロコン (SecYEG/Sec61) は,膜にわたるタンパク質の局所化を促進する.
- SecA ATPaseは,バクテリアの翻訳後の転位を駆動する.
研究 の 目的:
- SecAを含む生物から SecYE トランスロコンの高解像度構造を決定する.
- SecA-SecYE相互作用のメカニズムとタンパク質転位におけるその役割を解明する.
主な方法:
- X線結晶学 (3.2-A解像度)
- アンチ-SecY Fab 断片を備えた複合形成である.
- 分子ダイナミクスシミュレーション
- ディスルフィードマッピング
主要な成果:
- SecYEトランスロコンの"開く前の状態"が観察されました.
- SecAとFabの断片は,SecYの共通の部位に結合する.
- SecA結合は,SecYEにおける構成的移行を誘導するように見えます.
- 新しい SecA-SecYE インターフェースが特定され,協同的な構造の変化を示唆しました.
結論:
- SecYEのトランスロコンは,ダイナミックな"前開"状態で存在します.
- SecAとSecYの結合は,トランスロコンの形状の変化を開始するために重要である.
- SecAとSecYEの間の協力的な形状の変化は,機能的複合体の形成とタンパク質の転位に不可欠です.
関連する概念動画
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.
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...
Bacterial Translocation and Protein Secretion
Bacterial protein secretion involves translocation systems to ensure proteins reach their designated locations, including the plasma membrane, periplasm, outer membrane, or the external environment. These translocation systems are vital for bacterial physiology, supporting processes like membrane assembly, enzymatic activity in the periplasm, and interactions with the external environment. The division of labor between Sec and Tat pathways ensures efficiency in handling proteins with diverse...
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...
Protein Folding
Overview


