1Q5R

The Rhodococcus 20S proteasome with unprocessed pro-peptides

Summary for 1Q5R

• Entry DOI: 10.2210/pdb1q5r/pdb
• Related: 1Q5Q
• Descriptor: proteasome alpha-type subunit 1, proteasome beta-type subunit 1 (3 entities in total)
• Functional Keywords: proteasome assembly, pro-peptide, inter-subunit contacts, rhodococcus erythropolis, hydrolase
• Biological source: Rhodococcus erythropolis; More
• Cellular location: Cytoplasm (By similarity): Q53080 Q53079
• Total number of polymer chains: 14
• Total formula weight: 417125.49

Authors

Kwon, Y.D.,Nagy, I.,Adams, P.D.,Baumeister, W.,Jap, B.K. (deposition date: 2003-08-08, release date: 2003-12-16, Last modification date: 2024-02-14)

Primary citation

Kwon, Y.D.,Nagy, I.,Adams, P.D.,Baumeister, W.,Jap, B.K.
Crystal structures of the Rhodococcus proteasome with and without its pro-peptides: implications for the role of the pro-peptide in proteasome assembly.
J.Mol.Biol., 335:233-245, 2004

PubMed Abstract: 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.

PubMed: 14659753
DOI: 10.1016/j.jmb.2003.08.029

Experimental method

X-RAY DIFFRACTION (3.1 Å)