Protein and gene structures of 20S and 26S proteasomes.
The two types of proteasomes with apparent sedimentation coefficients of 20S and 26S consist of a number of heterogeneous polypeptides and are unusually large protein complexes of approximately 750 kDa and 2000 kDa, respectively. The 26S proteasome is a cylindrical caterpillar-shaped complex with a symmetrical assembly of a four-layered central 20S proteasome and two terminal 22S regulators each with a V-like structure. The central core and the terminal structures are formed by multiple polypeptides with molecular masses of 21-31 kDa and 28-112 kDa, respectively. We have been studying their detailed structures by protein-chemical and molecular biological techniques. In this review, we summarize the structural features of eukaryotic 20S and 26S proteasomes. We also discuss the possible function(s) of the terminal multi-protein regulator complex based on current information.
Tanaka
K
K
Institute for Enzyme Research, University of Tokushima, Japan.
Tamura
T
T
Tanahashi
N
N
Tsurumi
C
C
D000818:Animals; D003546:Cysteine Endopeptidases / Q000737:chemistry* / Q000235:genetics; D005057:Eukaryotic Cells / Q000201:enzymology; D005809:Genes, Regulator; D008970:Molecular Weight; D009097:Multienzyme Complexes / Q000737:chemistry* / Q000235:genetics; D005810:Multigene Family
D009097:Multienzyme Complexes; D003546:Cysteine Endopeptidases