Related Experiment Video
Updated: Mar 31, 2026
09:57
Examining Proteasome Assembly with Recombinant Archaeal Proteasomes and Nondenaturing PAGE: The Case for a Combined Approach
Published on: December 17, 2016
7.0K
ATP binding to neighbouring subunits and intersubunit allosteric coupling underlie proteasomal ATPase function
Young-Chan Kim1, Aaron Snoberger1, Jane Schupp1
1Department of Biochemistry, West Virginia University, 1 Medical Center Drive, Morgantown, West Virginia 26506, USA.
Nature Communications
|October 15, 2015
Summary
The proteasome uses ATP binding to two subunits to control substrate entry and degradation. Arginine fingers in archaeal proteasomes coordinate these effects, revealing how ATP hydrolysis drives protein breakdown.
Area of Science:
- Biochemistry
- Molecular Biology
- Cellular Biology
Background:
- The proteasome is a crucial cellular machine responsible for protein degradation.
- Its function is regulated by a hexameric ATPase complex that controls substrate access and translocation.
- The precise mechanisms by which ATP binding and hydrolysis coordinate these allosteric events remain incompletely understood.
Purpose of the Study:
- To elucidate the spatial and temporal coordination of allosteric effects by ATP binding and hydrolysis in proteasomal ATPases.
- To investigate the role of conserved arginine fingers in mediating ATP-driven allosteric regulation.
- To understand the dynamics of ring resetting and its relation to ATP hydrolysis in polypeptide translocation.
Main Methods:
- Förster Resonance Energy Transfer (FRET) imaging to study ATP binding dynamics.
- High-affinity ATP binding assays.
- Rapid kinetics analysis to probe hydrolysis mechanisms.
- Comparative studies using eukaryotic proteasomal ATPases (RPTs) and archaeal proteasome ATPase (PAN).
Main Results:
- Proteasomal ATPases (RPTs and PAN) exhibit high-affinity ATP binding at neighboring subunits, consistent with the 26S ATPase topology.
- Two conserved arginine fingers at the subunit interface in PAN act as a single allosteric unit, mediating ATP binding effects without changing nucleotide binding patterns.
- Ring resetting in the hydrolysis mechanism is explained by thermodynamic equilibrium binding of ATP.
Conclusions:
- ATP binding and hydrolysis in proteasomal ATPases are spatially and temporally coordinated by distinct allosteric networks.
- Conserved arginine fingers play a key role in mediating ATP-driven allosteric regulation for substrate translocation.
- These findings support a model of cooperative allosteric networks driving polypeptide translocation into the 20S proteasome for degradation.
Related Concept Videos
01:48ATP Synthase: Mechanism
18.8K
In animals, the mitochondrial F1F0 ATP synthase is the key protein that synthesizes ATP molecules through a complex catalytic mechanism. While the nuclear genome encodes the majority of ATP synthase subunits, the mitochondrial genome encodes some of the enzyme's most critical components. The formation of this multi-subunit enzyme is a complex multi-step process regulated at the level of transcription, translation, and assembly. Defects in one or more of these steps can result in decreased...
18.8K
01:19Allosteric Proteins-ATCase
6.9K
Binding sites linkages can regulate a protein's function. For example, enzyme activity is often regulated through a feedback mechanism where the end product of the biochemical process serves as an inhibitor.
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis...
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis...
6.9K
01:18ATP Synthase: Structure
17.7K
ATP synthase or ATPase is among the most conserved proteins found in bacteria, mammals, and plants. This enzyme can catalyze a forward reaction in response to the electrochemical gradient, producing ATP from ADP and inorganic phosphate. ATP synthase can also work in a reverse direction by hydrolyzing ATP and generating an electrochemical gradient. Different forms of ATP synthases have evolved special features to meet the specific demands of the cell. Based on their specific feature, ATP...
17.7K
00:49Ligand Binding and Linkage
6.0K
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...
6.0K
01:17The Proteasome Structure
2.2K
The ubiquitin-proteasome pathway is a well-known mechanism utilized by eukaryotic cells to remove cytoplasmic proteins that are misfolded, damaged, or no longer needed. In this pathway, the protein that needs to be eliminated undergoes a process called ubiquitination, where a chain of ubiquitin molecules is attached to the 48th lysine residue of the target protein. This ubiquitin modification helps the proteasome distinguish between a target protein and a healthy protein.
The proteasome is an...
The proteasome is an...
2.2K
01:58Cooperative Allosteric Transitions
9.4K
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...
9.4K