title: Subunit arrangement in the human 20S proteasome.
abstract: In human 20S proteasomes two copies of each of seven different alpha-type and seven different beta-type subunits are assembled to form a stack of four seven-membered rings, giving the general structure alpha(1-7), beta(1-7), beta(1-7), alpha(1-7). By means of immunoelectron microscopy and chemical crosslinking of neighboring subunits, we have determined the positions of the individual subunits in the proteasome. The topography shows that for the trypsin-like, the chymotrypsin-like, and the postglutamyl cleaving activities, the pairs of beta type subunits, which are thought to form active sites, are nearest neighbors.
authors.affiliation: Diabetes Forschungsinstitut, Düsseldorf, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Kopp
authors.forename: K B
authors.initials: KB
authors.lastname: Hendil
authors.forename: B
authors.initials: B
authors.lastname: Dahlmann
authors.forename: P
authors.initials: P
authors.lastname: Kristensen
authors.forename: A
authors.initials: A
authors.lastname: Sobek
authors.forename: W
authors.initials: W
authors.lastname: Uerkvitz
mesh_terms: D000595:Amino Acid Sequence; D003546:Cysteine Endopeptidases / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D016253:Microscopy, Immunoelectron; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000737:chemistry* / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex; D011487:Protein Conformation; D013329:Structure-Activity Relationship
chemical_list: D009097:Multienzyme Complexes; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex