REFOLDING OF DENATURED TRICHOSANTHIN IN THE PRESENCE OF GROEL

The stability of trichosanthin (TCS), a 27-kDa ribosome-inactivating p rotein, was investigated in the presence of guanidinium chloride (GdnH Cl). The process of unfolding was monitored by CD and fluorescence spe ctroscopy, Both methods show the presence of partially folded intermed iates. Unfolding of TCS is attained in BM GdnHCl, but the inactive spe cies recover a good deal of its DNase activity upon dilution with buff er containing GroEL and ATP, The mechanism of recognition of unfolded TCS by GroEL was studied by fluorescence spectroscopy. (C) 1998 Academ ic Press.