Crystal Structures of the Rhodococcus Proteasome with and without its Pro-peptides: Implications for the Role of the Pro-peptide in Proteasome Assembly
| Autor: | Paul D. Adams, István Nagy, Young Do Kwon, Wolfgang Baumeister, Bing K. Jap |
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| Rok vydání: | 2004 |
| Předmět: |
Models
Molecular Proteasome Endopeptidase Complex Protein Conformation Plasma protein binding Crystallography X-Ray Protein structure Multienzyme Complexes Structural Biology Rhodococcus Amino Acid Sequence Binding site Molecular Biology Peptide sequence Enzyme Precursors Binding Sites biology Chemistry Thermoplasma biology.organism_classification Cell biology Enzyme Activation Cysteine Endopeptidases Protein Subunits Proteasome Biochemistry Proteasome assembly Mutation Protein Binding |
| Zdroj: | Journal of Molecular Biology. 335:233-245 |
| ISSN: | 0022-2836 |
| Popis: | To understand the role of the pro-peptide in proteasome assembly, we have determined structures of the Rhodococcus proteasome and a mutant form that prevents the autocatalytic removal of its pro-peptides. The structures reveal that the pro-peptide acts as an assembly-promoting factor by linking its own beta-subunit to two adjacent alpha-subunits, thereby providing a molecular explanation for the observed kinetics of proteasome assembly. The Rhodococcus proteasome has been found to have a substantially smaller contact region between alpha-subunits compared to those regions in the proteasomes of Thermoplasma, yeast, and mammalian cells, suggesting that a smaller contact area between alpha-subunits is likely the structural basis for the Rhodococcus alpha-subunits not assembling into alpha-rings when expressed alone. Analysis of all available beta-subunit structures shows that the contact area between beta-subunits within a beta-ring is not sufficient for beta-ring self-assembly without the additional contact provided by the alpha-ring. This appears to be a fail-safe mechanism ensuring that the active sites on the beta-subunits are activated only after proteasome assembly is complete. |
| Databáze: | OpenAIRE |
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