Figure 6

The unfolding transition of PrP variants in the presence of urea at pH 7 (♦) and pH 4 (■) at a concentration of 5 μM.
The ellipticity at 222 nm was monitored by circular dichroism, normalised and the average of 3 readings were plotted against the increasing concentration of urea. A curve representing a bi-phasic transition was fitted to each set of data to allow the calculation of midpoints of the transitions (A) recMoPrP; (B) recMoPrP-S169N; (C) recMoPrP-N173T; (D) recMoPrP-S169N/N173T.