Related Experiment Video
Updated: May 10, 2026
06:06
In Vitro Analysis of E3 Ubiquitin Ligase Function
Published on: May 14, 2021
Macromolecular juggling by ubiquitylation enzymes
Sonja Lorenz1, Aaron J Cantor, Michael Rape
1Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA.
BMC Biology
|June 27, 2013
Summary
Protein ubiquitination relies on E1, E2, and E3 enzymes. Large conformational changes in E1 and E3 enzymes facilitate efficient ubiquitin transfer, as shown by crystallographic studies.
Area of Science:
- Biochemistry
- Structural Biology
- Molecular Biology
Background:
- Protein posttranslational modification is crucial for cellular function.
- Ubiquitination, mediated by E1, E2, and E3 enzymes, regulates numerous cellular processes.
- E1 and E3 enzymes undergo significant conformational changes during ubiquitin transfer.
Purpose of the Study:
- To review conformational changes in E1 and E3 enzymes.
- To highlight the role of these changes in ubiquitin handover.
- To present insights from crystallographic studies.
Main Methods:
- Review of existing crystallographic data.
- Analysis of domain interface remodeling in E1 and E3 enzymes.
- Focus on conformational transformations during catalytic cycles.
Main Results:
- E1 and E3 enzymes exhibit substantial conformational flexibility.
- Remodeling of domain interfaces is key to enzyme function.
- These dynamic changes enable precise and regulated ubiquitin transfer.
Conclusions:
- Conformational plasticity is essential for the ubiquitin-proteasome system.
- Crystallography provides critical structural insights into enzyme mechanisms.
- Understanding these transformations aids in deciphering ubiquitination regulation.
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02:04Covalently Linked Protein Regulators
Proteins can undergo many types of post-translational modifications, often in response to changes in their environment. These modifications play an important role in the function and stability of these proteins. Covalently linked molecules include functional groups, such as methyl, acetyl, and phosphate groups, and also small proteins, such as ubiquitin. There are around 200 different types of covalent regulators that have been identified.
These groups modify specific amino acids in a protein.
These groups modify specific amino acids in a protein.
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01:57Protein Complexes with Interchangeable Parts
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02:58Regulated Protein Degradation
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02:18The Proteasome
Eukaryotic cells can degrade proteins through several pathways. One of the most important amongst these is the ubiquitin-proteasome pathway. It helps the cell eliminate the misfolded, damaged, or unwarranted cytoplasmic proteins in a highly specific manner.
In this pathway, the target proteins are first tagged with small proteins called ubiquitin. A series of enzymes carry out the ubiquitination of the target proteins - E1 (ubiquitin-activating enzyme), E2 (ubiquitin-conjugating enzyme), and E3...
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