関連する実験動画

Updated: Mar 13, 2026

Studies of Chaperone-Cochaperone Interactions using Homogenous Bead-Based Assay

Studies of Chaperone-Cochaperone Interactions using Homogenous Bead-Based Assay

Published on: July 21, 2021

クライアント結合の代替モードは,Hsp70の機能的な可塑性を可能にします

Alireza Mashaghi¹, Sergey Bezrukavnikov¹, David P Minde¹

¹FOM institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands.

|November 4, 2016

まとめ

Hsp70チャペロン (DnaK) は,展開された鎖だけでなく,様々な折り畳み段階のタンパク質を安定させます. タンパク質の折りたたみと結合に影響を及ぼします

科学分野:

分子生物学
生物化学
タンパク質ダイナミクス

背景:

熱ショックタンパク質70 (Hsp70) は,タンパク質ホメオスタシスに不可欠であり,折り畳みを助け,結合を防止し,タンパク質の流通を調節します.
Hsp70は,ATP駆動の蓋で覆われたペプチド結合槽を通して基板と相互作用すると考えられています.
異なる折り畳み状態でのHsp70基板相互作用を直接観察し,蓋のダイナミクスを理解することは困難でした.

研究の目的:

Hsp70 (DnaK) と様々な構成状態のタンパク質基板の相互作用メカニズムを調査する.
基板の結合と安定化における Hsp70 蓋と溝の役割を明らかにする.
タンパク質の折りたたみと結合に関する様々なHsp70結合モードの影響を調査する.

主な方法:

細菌のHsp70同種 (DnaK) とタンパク質基板の間の力および相互作用を直接測定するために光学ピンチを使用した.
DnaKによる展開された,部分的に折れた,およびほぼ本来のタンパク質構造の結合と安定化を調査した.
切断された蓋と変異した溝のバリエーションを使用して,DnaKの蓋と溝の相乗効果の役割を調べました.

主要な成果:

DnaKは,展開されたポリペプチド鎖だけでなく,部分的に折れた,ほぼ原生タンパク質構造も結合し,安定させます.
Hsp70の蓋と溝は,折りたたまれた構造を安定させるため,連携して機能し,蓋の断片化や溝の変異は,この機能を著しく損なう.
Hsp70は,タンパク質の安定化と不安定化において,核酸調節による二重の役割を果たし,様々なタンパク質コンフォマーを保護することによって,後期段階の折りたたみに影響を与え,結合を抑制する.

結論:

Hsp70機能の定式モデルは,折りたたまれたタンパク質状態との相互作用および安定化を含むように拡張される.
Hsp70が複数の折り畳み段階でタンパク質の構造を調節する能力は,タンパク質の折り畳み,細胞のプロテオスタシス,および疾患に重大な影響を及ぼします.
これらの発見は,多様な基板相互作用メカニズムを通じて細胞タンパク質の恒常性を維持するHsp70の汎用性を強調しています.

さらに関連する動画

Defining Hsp33's Redox-regulated Chaperone Activity and Mapping Conformational Changes on Hsp33 Using Hydrogen-deuterium Exchange Mass Spectrometry

Defining Hsp33's Redox-regulated Chaperone Activity and Mapping Conformational Changes on Hsp33 Using Hydrogen-deuterium Exchange Mass Spectrometry

Published on: June 7, 2018

Biochemical Reconstitution of Steroid Receptor•Hsp90 Protein Complexes and Reactivation of Ligand Binding

Biochemical Reconstitution of Steroid Receptor•Hsp90 Protein Complexes and Reactivation of Ligand Binding

Published on: September 21, 2011

関連する概念動画

Ligand Binding and Linkage

Ligand Binding and Linkage

Allosteric proteins have more than one ligand binding site; the binding of a ligand to any of these sites influences the binding of ligands to the other sites. When a protein is allosteric, its binding sites are called coupled or linked. In the case of enzymes, the site that binds to the substrate is known as the active site and the other site is known as the regulatory site. When a ligand binds to the regulatory site, this leads to conformational changes in the protein that can influence...

Molecular Chaperones and Protein Folding

Molecular Chaperones and Protein Folding

The native conformation of a protein is formed by interactions between the side chains of its constituent amino acids. When the amino acids cannot form these interactions, the protein cannot fold by itself and needs chaperones. Notably, chaperones do not relay any additional information required for the folding of polypeptides; the native conformation of a protein is determined solely by its amino acid sequence. Chaperones catalyze protein folding without being a part of the folded protein.
The...

Cooperative Allosteric Transitions

Cooperative Allosteric Transitions

Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand binds to any of these subunits, it triggers a conformational change that affects the binding sites in the other subunits; this can change the affinity of the other sites for their respective ligands. The ability of the protein to change the shape of its binding site is attributed to the presence of a mix of flexible and stable segments in the...

Conserved Binding Sites

Conserved Binding Sites

Many proteins’ biological role depends on their interactions with their ligands, small molecules that bind to specific locations on the protein known as ligand-binding sites. Ligand-binding sites are often conserved among homologous proteins as these sites are critical for protein function.
Binding sites are often located in large pockets, and if their location on a protein’s surface is unknown, it can be predicted using various approaches. The energetic method computationally...

Protein Complexes with Interchangeable Parts

Protein Complexes with Interchangeable Parts

Groups of proteins may form a complex where each protein in this complex has a different role in the overall execution of the complex’s function. Often some of the proteins in the complex can be replaced by a closely related variant to give a complex that contains many of the same components yet is functionally distinct.
The SCF ubiquitin ligase is a protein complex of five individual proteins. This complex attaches ubiquitin to other target proteins to mark them for degradation. In order...

Ligand Binding Sites

Ligand Binding Sites

Proteins are dynamic macromolecules that carry out a wide variety of essential processes; however, the activities of most proteins depend on their interactions with other molecules or ions, known as ligands.
Protein-ligand interactions are quite specific; even though numerous potential ligands surround a cellular protein at any given time, only a particular ligand can bind to that protein. Moreover, a ligand binds only to a dedicated area on the surface of the protein, known as the...