title: Conformational changes in the 20S proteasome upon macromolecular ligand binding analyzed with monoclonal antibodies.
abstract: Proteasomes interact with a variety of macromolecular ligands that modulate their ability to degrade peptide and protein substrates. The effector PA28 increases the peptidase activities of proteasomes whereas HSP90 and alpha-crystallin inhibit a peptide-hydrolyzing activity. Four monoclonal antibodies were used as probes to detect conformational changes of proteasome subunits. Conformational changes in alpha- or beta-subunits were found upon binding PA28, HSP90, alpha-crystallin, and the substrate casein but not with the peptide substrate analogs calpain inhibitor 1 (Ac-Leu-Leu-norleucinal), calpain inhibitor 2 (Ac-Leu-Leu-methioninal), or MG 132 (N-Cbz-Leu-Leu-leucinal).
authors.affiliation: Unité de Biochimie Cellulaire, Institut Pasteur, 28 rue du Dr. Roux, Paris, 75724, France.
authors.forename: M
authors.initials: M
authors.lastname: Conconi
authors.forename: L
authors.initials: L
authors.lastname: Djavadi-Ohaniance
authors.forename: W
authors.initials: W
authors.lastname: Uerkvitz
authors.forename: K B
authors.initials: KB
authors.lastname: Hendil
authors.forename: B
authors.initials: B
authors.lastname: Friguet
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000915:Antibody Affinity; D001666:Binding Sites, Antibody; D002364:Caseins / Q000378:metabolism; D003459:Crystallins / Q000378:metabolism; D003546:Cysteine Endopeptidases / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism*; D015853:Cysteine Proteinase Inhibitors / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D006023:Glycoproteins / Q000378:metabolism; D018841:HSP90 Heat-Shock Proteins / Q000378:metabolism; D006801:Humans; D007976:Leupeptins / Q000378:metabolism; D008024:Ligands; D009097:Multienzyme Complexes / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism*; D009124:Muscle Proteins; D009842:Oligopeptides / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex; D011487:Protein Conformation; D011506:Proteins / Q000378:metabolism