ウイルスカプシドの成熟ダイナミクス: 移行中間状態の視覚化
1Laboratory of Structural Biology, National Institute of Arthritis, Musculoskeletal and Skin Diseases, Bethesda, Maryland 20892, USA.
Cell
|February 5, 2000
まとめ
HK97バクテリオファグにおけるカプシドの成熟には,2段階の組み立てプロセスが含まれています. 酸性pHは膨張を誘発し,このダイナミックなタンパク質の折りたたみのような移行中に明確な中間構造を明らかにします.
科学分野:
- 構造生物学 構造生物学とは
- ウイルス学 ウイルス学 ウイルス学
- バイオフィジックス 生物物理学
背景:
- HK97のバクテリオファージの組み立ては,ポリメリゼーションと成熟という2段階のプロセスに従います.
- 成熟にはタンパク質分解があり,膨張の準備ができている転移安定粒子が生成されます.
- この主要な構造的移行は,安定したウイルス粒子の形成に不可欠です.
研究 の 目的:
- HK97カプシド前駆体のインビトロ膨張過程を調査する.
- カプシドの成熟過程における分子機構と中間構造を解明する.
- カプシドの成熟をダイナミックなプロセスとして視覚化します.
主な方法:
- 酸性pHを用いたカプシド膨張の誘導.
- 構造分析のための時間分解のX線 difraktion.
- 高解像度イメージングのための冷凍電子顕微鏡.
主要な成果:
- カプシド膨張は,ストキャスティックサブトランジションを含む非同期プロセスです.
- 拡張過程で3つの異なる中間構造が特定されました.
- これらの中間物質は,タンパク質の折りたたみで観察される移行状態に似ています.
結論:
- HK97カプシドの成熟は,タンパク質の折りたたみに似たダイナミックなプロセスです.
- 識別された中間物質は,膨張の分子イベントの洞察を提供します.
- このトランジションを理解することは,ウイルスのアセンブリメカニズムの鍵です.
関連する概念動画
00:56Viral Structure
59.0K
Viruses are extraordinarily diverse in shape and size, but they all have several structural features in common. All viruses have a core that contains a DNA- or RNA-based genome. The core is surrounded by a protective coat of proteins called the capsid. The capsid is composed of subunits called capsomeres. The capsid and genome-containing core are together known as the nucleocapsid.
59.0K
02:41Protein Complex Assembly
12.5K
Proteins can form homomeric complexes with another unit of the same protein or heteromeric complexes with different types. Most protein complexes self-assemble spontaneously via ordered pathways, while some proteins need assembly factors that guide their proper assembly. Despite the crowded intracellular environment, proteins usually interact with their correct partners and form functional complexes.
Many viruses self-assemble into a fully functional unit using the infected host cell to...
Many viruses self-assemble into a fully functional unit using the infected host cell to...
12.5K
01:28Maturation of Endosomes
5.1K
The early endosome containing internalized molecules matures through transformations in its location, morphology, intraluminal pH, and membrane protein composition. Together, these changes result in a more acidic late endosome that contains multiple intraluminal vesicles; therefore, the late endosome is also called a multivesicular body (MVB).
Changes in location
The maturing endosome moves along microtubules from the periphery of the cell towards the perinuclear region. This movement of the...
Changes in location
The maturing endosome moves along microtubules from the periphery of the cell towards the perinuclear region. This movement of the...
5.1K
01:38Intralumenal Vesicles and Multivesicular Bodies
4.0K
Intraluminal vesicles (ILVs) are small vesicles 50-80 nm in diameter formed during the maturation of early endosomes. A specialized endosome containing numerous ILVs is called a multivesicular body (MVB). ILVs contain internalized molecules such as antigens, nucleic acids, proteins, and metabolites. Some of these molecules are released from the MVBs inside exosomes and are transported to other cells. Other MVBs contain molecules that are retained in the ILVs and are later degraded within the...
4.0K
01:32Pinching-off of Coated Vesicles
3.1K
Vesicle budding is orchestrated by distinct cytosolic proteins such as adaptor proteins, coat proteins, and GTPases. To initiate vesicle budding, membrane-bending proteins containing crescent-shaped BAR domains bind to the lipid heads in the bilayer and distort the membrane to form a protein-coated vesicle bud. Adaptors proteins such as AP2 for clathrin-coated vesicles can nucleate on the deformed membrane. Finally, coat proteins such as clathrin or COPI and COPII assemble into a coat forming...
3.1K
01:26Size and Structure of Viral Genomes
1.2K
Viral genomes exhibit remarkable diversity in size, structure, and composition, influencing their replication strategies and interactions with host cells. These genomes consist of either DNA or RNA and may be linear or circular. Additionally, they can be single-stranded or double-stranded, with each configuration affecting how the virus propagates within a host. RNA viruses, for instance, generally have smaller genomes than DNA viruses, a factor that contributes to their high mutation rates and...
1.2K