Chaperonins induce an amyloid-like transformation of ovine prion protein: The fundamental difference in action between eukaryotic TRiC and bacterial GroEL

► We compared effects caused by bacterial GroEL and eukaryotic TRiC on the ovine PrP. ► Both chaperonins bind the native prion protein. ► GroEL produces amyloid-like forms of ovine PrP in the presence of Mg-ATP. ► TRiC produces amyloid-like forms of ovine PrP only in the absence of Mg-ATP. ► Chaperonin TRiC induces the formation of amyloid fibrils from ovine PrP.