In vitro evidence that hsp90 contains two independent chaperone sites.
Hsp90 is an abundant and constitutively expressed stress protein and molecular chaperone. Here we dissected human hsp90 into three major domains to identify the putative chaperone site at which hsp90 binds unfolded polypeptide. Surprisingly, both the N-terminal and the C-terminal domain of hsp90 prevent the aggregation of denatured polypeptides. The chaperone activity of the N-domain is inhibited by geldanamycin, a specific inhibitor of hsp90-mediated protein refolding. While both domains suppress protein aggregation, only the C-domain binds an antigenic peptide derived from VSV G. Based on these results, hsp90 may be the first chaperone to contain two independent chaperone sites with differential specificity.
Young
J C
JC
Cellular Biochemistry, Max-Planck-Institut für Biochemie, Martinsried, Germany.
Schneider
C
C
Hartl
F U
FU
D000595:Amino Acid Sequence; D016227:Benzoquinones; D001665:Binding Sites; D019281:Dimerization; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005982:Glutathione Transferase; D018841:HSP90 Heat-Shock Proteins / Q000737:chemistry* / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D047029:Lactams, Macrocyclic; D008156:Luciferases / Q000737:chemistry* / Q000378:metabolism; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D011489:Protein Denaturation; D017510:Protein Folding; D011809:Quinones / Q000494:pharmacology; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism
D016227:Benzoquinones; D004791:Enzyme Inhibitors; D018841:HSP90 Heat-Shock Proteins; D047029:Lactams, Macrocyclic; D010446:Peptide Fragments; D011809:Quinones; D011993:Recombinant Fusion Proteins; D008156:Luciferases; D005982:Glutathione Transferase; C001277:geldanamycin