CATH Classification

Domain Context

CATH Clusters

Superfamily Glutamine Phosphoribosylpyrophosphate, subunit 1, domain 1
Functional Family Proteasome subunit beta

Enzyme Information

3.4.25.1
Proteasome endopeptidase complex.
based on mapping to UniProt P28061
Cleavage of peptide bonds with very broad specificity.
-!- A 20-S protein composed of 28 subunits arranged in four rings of seven. -!- The outer rings are composed of alpha subunits, but the beta subunits forming the inner rings are responsible for peptidase activity. -!- In eukaryotic organisms there are up to seven different types of beta subunits, three of which may carry the N-terminal threonine residues that are the nucleophiles in catalysis, and show different specificities. -!- The molecule is barrel-shaped, and the active sites are on the inner surfaces. -!- Terminal apertures restrict access of substrates to the active sites. -!- Inhibited by mercurial reagents and some inhibitors of serine endopeptidases. -!- Belongs to peptidase family T1. -!- Formerly EC 3.4.22.21, EC 3.4.24.5 and EC 3.4.99.46.

UniProtKB Entries (1)

P25156
PSA_THEAC
Thermoplasma acidophilum DSM 1728
Proteasome subunit alpha

PDB Structure

PDB 1PMA
External Links
Method X-RAY DIFFRACTION
Organism Escherichia
Primary Citation
Crystal structure of the 20S proteasome from the archaeon T. acidophilum at 3.4 A resolution.
Lowe, J., Stock, D., Jap, B., Zwickl, P., Baumeister, W., Huber, R.
Science