酵母オリゴサカリトランスフェラーゼ複合体の構造は,真核生物のN-グリコシル化に洞察を与える
Rebekka Wild1, Julia Kowal1, Jillianne Eyring2
1Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zurich, CH-8093 Zurich, Switzerland.
まとめ
酵母オリゴサカリルトランスフェラーゼ (OST) の原子構造は,この必須酵素複合体が基板にどのように結合するかを明らかにする. 活性部位の構成により,エンドプラズマの網膜にタンパク質を効率的にグリコシル化することができます.
科学分野:
- 生物化学
- 分子生物学
- 構造生物学
背景:
- オリゴサカリルトランスフェラーゼ (OST) は,エンドプラズマ網膜に位置する重要な酵素複合体です.
- N-リンクド・グリコシル化と呼ばれるプロセスで,オリゴサッカライドの分泌タンパク質への転移を触媒化します.
- タンパク質の折りたたみ,安定性,機能には効率的なグリコシレーションが不可欠です.
研究 の 目的:
- クリオ電子顕微鏡を用いて酵母OSTの原子構造を決定する.
- OSTのサブユニット配置と基板結合メカニズムを明らかにする.
- エンドプラズマの網膜にポリペプチドを効率的にグリコシル化する方法を理解する.
主な方法:
- 高解像度構造データを得るために,冷凍電子顕微鏡 (cryo-EM) が使用された.
- 詳細な構造分析を行い,保存されたサブユニットの配置とアクティブサイトの特徴を特定しました.
- ドリコールピロホスファートとオリゴサカリドの基板結合部位は複合体内でマッピングされた.
主要な成果:
- 原子構造は OSTサブユニットの保存された配置を明らかにした.
- 触媒STT3サブユニットの活性部位は基板にアクセスできます.
- ドリホルピロフォスファートドナーとオリゴサカリドには,非触媒的サブユニットを含む特定の結合ポケットが特定されました.
- 受容体ポリペプチド結合部位が酸化還元酵素ドメインまたはトランスロコンに近いことが観察された.
結論:
- 決定された構造は,OSTのメカニズムに前例のない洞察を提供します.
- 酵素の構造は,効率的な基質アクセスとオリゴサッカリドの転送を容易にする.
- OSTの構造と機能を理解することは,エンドプラズマの網膜におけるタンパク質の処理を理解する上で鍵となる.
関連する概念動画
Yeast Signaling
17.4K
Yeasts are single-celled organisms, but unlike bacteria, they are eukaryotes (cells with a nucleus). Cell signaling in yeast is similar to signaling in other eukaryotic cells. A ligand, such as a protein or a small molecule released from a yeast cell, attaches to a receptor on the cell surface. The binding stimulates second-messenger kinases to activate or inactivate transcription factors that further regulate gene expression. Many of the yeast intracellular signaling cascades have similar...
17.4K
Replication in Eukaryotes
206.0K
Overview
206.0K
The Eukaryotic Promoter Region
19.0K
The eukaryotic promoter region is a segment of DNA located upstream of a gene. It contains an RNA polymerase binding site, a transcription start site, and several cis-regulatory sequences. The proximal promoter region is located in the vicinity of the gene and has cis-regulatory sequences and the core promoter. The core promoter is the binding site for RNA polymerase and is usually located between -35 and +35 nucleotides from the transcription start site. The distal promoter regions are...
19.0K
Eukaryotic RNA Polymerases
27.2K
RNA Polymerase (RNAP) is conserved in all animals, with bacterial, archaeal, and eukaryotic RNAPs sharing significant sequence, structural, and functional similarities. Among the three eukaryotic RNAPs, RNA Polymerase II is most similar to bacterial RNAP in terms of both structural organization and folding topologies of the enzyme subunits. However, these similarities are not reflected in their mechanism of action.
All three eukaryotic RNAPs require specific transcription factors, of which the...
All three eukaryotic RNAPs require specific transcription factors, of which the...
27.2K
Protein Glycosylation
9.8K
Glycosylation, the most common post-translational modification for proteins, serves diverse functions. Adding sugars to proteins makes the proteins more resistant to proteolytic digestion. Glycosylated proteins can act as markers and receptors to promote cell-cell adhesion. Additionally, they have many essential quality control functions in the cell, such as correct protein folding and facilitating transport of misfolded proteins to the cytosol, which can be degraded.
Glycosylation occurs in...
Glycosylation occurs in...
9.8K
Assembly of Complex Microtubule Structures
2.5K
Complex microtubule structures are present in resting cells and in dividing cells. In resting cells, they are responsible for maintaining the cellular architecture, tracks for intracellular transport, positioning of organelles, assembly of cilia and flagella. They mediate the bipolar spindle assembly for chromosomal segregation and positioning of the cell division plate in dividing cells. The formation of microtubule complex structures depends on the cell type, cell stage, and cell function.
2.5K


