RIBONUCLEASE-T1 HAS DIFFERENT DIMENSIONS IN THE THERMALLY AND CHEMICALLY DENATURED STATES - A DYNAMIC LIGHT-SCATTERING STUDY

Ribonuclease T1 can be unfolded and refolded without forming noticeabl e amounts of aggregates allowing to characterise the dimensions of a p rotein in different denatured states in terms of the Stokes radius R(S ). Upon thermal unfolding R(S) increases from 1.74 nm at 20 degrees C to 2.14 nm at 60 degrees C. By contrast, R(S)=2.40 nm was obtained at 5.3 M guanidinium chloride (GuHCl) and 20 degrees C. Heating from 20 d egrees C to 70 degrees C in the presence of 5.3 M GuHCl led to a 5% de crease in R(S). (C) 1997 Federation of European Biochemical Societies.