OmpFポリントリマーの毛穴を通過した受動タンパク質による膜越えエピトープの供給
Sejeong Lee1, Nicholas G Housden2, Sandra A Ionescu1
1Chemistry Research Laboratory, University of Oxford, Oxford OX1 3TA, U.K.
Journal of the American Chemical Society
|July 3, 2020
まとめ
バクテリオシンColE9は,Escherichia coliの外膜のOmpFポリンを被動輸入に使用しています. その非構造的N端の転位ドメインはOmpFサブユニットを通過し,安定した不可逆的な複合体を形成します.
科学分野:
- バクテリアの外膜輸送
- タンパク質の転位メカニズム
- 分子生物物理学
背景:
- グラム陰性細菌の外膜 (OM) は,栄養素と抗生物質の拡散のためにトリメアポリンを使用する.
- ColE9のようなバクテリオシンは,これらのポリンチャネルを悪用して,よく理解されていないメカニズムで細胞に侵入します.
研究 の 目的:
- ColE9エンドヌクレアースバクテリオシンの内在的に非構造的N末端転位領域 (IUTD) がOmpFポリン経由でEscherichia coli OMを通過するメカニズムを解明する.
主な方法:
- 平面性脂質二層の単一チャネルの電気記録
- タンパク質の工学技術
- 単一分子運動分析
主要な成果:
- IUTDの輸入は,OmpFの毛穴結合エピトープとの方向性バイアスの弱い相互作用によって引き起こされる.
- 2つのOmpFサブユニットを通過するIUTDの60以上のアミノ酸.
- IUTDは細胞外側から侵入し,周辺プラズマに転移し,複雑な再侵入と結合プロセスを経る.
結論:
- 輸送と結合の過程は不可逆的なフックのような組み立てを生み出します
- このアセンブリは,OmpFサブユニット間のインポート活性化ペプチドエピトープを制限し,バクテリオシン転位を詳細に説明します.
関連する概念動画
Insertion of Multi-pass Transmembrane Proteins in the RER
17.0K
The rough ER membrane synthesizes, assembles, and embeds transmembrane proteins in diverse topologies. These proteins function as transporters or channels and can remain in the ER membrane or are sent to the Golgi complex, lysosome, and cell membrane.
The multipass transmembrane proteins are the type IV integral membrane proteins with multiple topogenic sequences determining their spatial arrangement in the ER membrane. Nearly all multipass proteins lack a cleavable signal sequence and use...
The multipass transmembrane proteins are the type IV integral membrane proteins with multiple topogenic sequences determining their spatial arrangement in the ER membrane. Nearly all multipass proteins lack a cleavable signal sequence and use...
17.0K
Structure of Porins
3.7K
Mitochondria, chloroplasts, and gram-negative bacteria have transmembrane, beta-barrel proteins called porins to mediate the free diffusion of ions and metabolites across the membrane. Mitochondrial porin precursors contain conserved amino acid sequences called beta signals at their C-terminal. Beta signals have a motif of PoXGXXHyXHy (Po-Polar, X-Any amino acid, G-Glycine, Hy-LargeHydrophobic), which are crucial for precursor recognition to initiate precursor assembly. Beta-barrel...
3.7K
Translocation of Proteins into the Mitochondria
11.6K
Mitochondrial precursors are translocated to the internal subcompartments via independent mechanisms involving distinct protein machineries called translocases.
Sorting of outer membrane proteins:
Mitochondrial outer membrane proteins are of two types: the transmembrane, beta-barrel porins, and the membrane-anchored, alpha-helical proteins. Beta-barrel porin precursors are translocated by the TOM complex and inserted into the outer mitochondrial membrane by the SAM complex. In contrast,...
Sorting of outer membrane proteins:
Mitochondrial outer membrane proteins are of two types: the transmembrane, beta-barrel porins, and the membrane-anchored, alpha-helical proteins. Beta-barrel porin precursors are translocated by the TOM complex and inserted into the outer mitochondrial membrane by the SAM complex. In contrast,...
11.6K
Protein Transport into the Inner Mitochondrial Membrane
4.6K
Nuclear encoded mitochondrial precursors are imported to the inner membrane in a multistep process involving two separate translocons, TIM22 and TIM23. TIM23 is a cation-selective pore that remains closed by the N terminal segment of the protein. Negative charges on the TIM23 act as a receptor for the incoming precursor, pulling the positively charged matrix-targeting sequence for peptide insertion and translocation.
Transport of mitochondrial precursors across the TIM23 channel is driven by...
Transport of mitochondrial precursors across the TIM23 channel is driven by...
4.6K
Porin Insertion in the Outer Mitochondrial Membrane
4.2K
Porins are beta-barrel proteins translocated to the mitochondrial outer membrane through the TOM complex into the intermembrane space. Porin precursors bind TIM chaperones within the intermembrane space and are guided to the Sorting and Assembly Machinery complex or SAM complex on the outer mitochondrial membrane.
Three models describe the assembly of porins by the SAM complex and their insertion into the outer membrane. Model 1 suggests that porins are assembled outside the SAM channel as the...
Three models describe the assembly of porins by the SAM complex and their insertion into the outer membrane. Model 1 suggests that porins are assembled outside the SAM channel as the...
4.2K
Insertion of Single-pass Transmembrane Proteins in the RER
15.9K
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...
15.9K


