Figure 3.

Combined effects of chaperones and partially denatured PrP^Sc on conversion. (A) Conversions obtained with partially denatured PrP^Sc (4 M urea pretreatment) with buffer alone, or with the indicated chaperones and control proteins (each at 5 μM). Mean values are from three to six independent measurements, with standard errors. (B) SDS/PAGE phosphorimage of representative conversion reactions obtained with untreated PrP^Sc (0) or PrP^Sc partially denatured in the presence of increasing urea concentrations (1–5 M), with or without chaperone (Hsp104 or GroEL, 3 μM). Only proteinase K-treated (+PK) samples are shown. (C) SDS/PAGE phosphorimage of representative conversion reactions obtained with Hsp104 (WT or mutant KT218), with or without ATP, and untreated or partially denatured PrP^Sc (4 M urea pretreatment). Only proteinase K-treated samples (+PK) are shown. (D) SDS/PAGE phosphorimage of representative conversion reactions obtained with partially denatured PrP^Sc (4 M urea pretreatment), with or without ATP, and with or without GroEL (WT or mutant D87K). Both proteinase K-treated (+PK; Lower) and untreated samples (−PK, one-fifth sample; Upper) are shown.