20s Core Particle
20s Core Particle - Related Videos
02:10
The Nucleosome Core Particle
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2020
Nucleosomes are the DNA-histone complex, where the DNA strand is wound around the histone core. The histone core is an octamer containing two copies of H2A, H2B, H3, and H4 histone proteins. The paradox Nucleosomes, paradoxically, perform two opposite functions simultaneously. On the one hand, their main responsibility is to protect the delicate DNA strands from physical damage and help achieve a higher compaction ratio. While on the other hand, they must allow polymerase enzymes to access DNA...
01:12
The Nucleosome Core Particle
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2023
Nucleosomes are the DNA-histone complex, where the DNA strand is wound around the histone core. The histone core is an octamer containing two copies of H2A, H2B, H3, and H4 histone proteins. Nucleosomes, paradoxically, perform two opposite functions simultaneously. On the one hand, their primary aim is to protect the delicate DNA strands from physical damage and help achieve a higher compaction ratio. On the other hand, they must allow polymerase enzymes to access histone-bound DNA during...
03:37
Subatomic Particles
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2020
Dalton was only partially correct about the particles that make up matter. All matter is composed of atoms, and atoms are composed of three smaller subatomic particles: protons, neutrons, and electrons. These three particles account for the mass and the charge of an atom. The Discovery of the Electron The first clue about the subatomic structure came at the end of the 19th century when J.J. Thomson discovered the electron using a cathode ray tube. This apparatus consisted of a sealed glass...
09:27
Encapsulation and Permeability Characteristics of Plasma Polymerized Hollow Particles
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Cited by 1 •
2012
We have used plasma enhanced chemical vapor deposition to deposit thin films ranging from a few nm to several 100 nm on nano-sized particles of various materials. We subsequently etch the core material to produce hollow nanoshells whose permeability is controlled by the thickness of the shell. We characterize the permeability of these coatings to small solutes and demonstrate that these barriers can provide sustained release of the core material over several days.
02:23
Visualizing the Effect of pH on Solubilization of the Influenza A Viral Core
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2026
Source: Stauffer, S. et al., In Vitro Disassembly of Influenza A Virus Capsids by Gradient Centrifugation. J. Vis. Exp. (2016)This video demonstrates the effect of pH on the solubilization of influenza A viral cores. Gel electrophoresis and protein staining reveal the progressive disassembly of the core structure under acidic conditions.
FAQs
The two outer alpha rings act as an entry-control layer for the proteolytic chamber. This arrangement helps restrict access to the internal beta-ring chamber, where peptide cleavage occurs, rather than exposing the catalytic environment directly to the cell. Studying this gate is important for understanding how proteolysis is confined within the proteasome.
N-terminal threonine residues on the beta subunits provide the cleavage activity that breaks unfolded polypeptides into shorter peptides. Their position inside the chamber places proteolysis within the core rather than at the particle surface. This organization connects the particle’s architecture to its ability to process proteins during cellular protein quality control.
The 20S core supplies the enclosed chamber and cleavage activity, whereas the 26S proteasome adds regulatory particles that recognize substrates and support ATP-dependent unfolding. This distinction separates protein processing into complementary roles: regulatory components help deliver and prepare substrates, while the core performs their proteolytic breakdown.
Regulatory particles connect substrate recognition and ATP-dependent unfolding with entry into the core chamber. These functions are especially important for proteins that must be selected and unfolded before cleavage. Consequently, studying the regulatory-core association helps explain how the proteasome coordinates substrate handling with controlled degradation rather than treating proteolysis as an isolated chemical reaction.
A useful structural analysis follows the four stacked rings, distinguishes the outer alpha rings from the inner beta rings, and locates the beta subunits’ N-terminal threonine residues. Researchers can then consider whether regulatory particles associate with the core. Together, these observations connect particle architecture with access control, unfolding, cleavage, and peptide production.
Its structure provides context for cellular protein balance because the proteasome removes damaged, misfolded, and short-lived proteins. The same system also informs studies of cell-cycle regulation and immune peptide generation. These applications show that the core is relevant both to routine protein quality control and to specialized biological outcomes involving regulated degradation and peptide production.
Proteasome inhibitors are important because they target mechanisms responsible for proteolytic activity, making the core relevant to studies of how protein degradation is controlled. Examining inhibitor effects can therefore help investigate the relationship between the chamber’s catalytic function and broader cellular consequences, including altered protein balance and pathways influenced by proteasome activity.