Biophysical characterization of AYE stabilization recapitulation mutants. (a) The far-UV CD spectra of 25 μM AYEwt, seven designed AYE mutants, and AYEdes in 25 mM Tris (pH 8.0), 50 mM NaCl, at 25 °C. (b) The CD signal at 220 nm as a function of GuHCl concentration for all the above proteins at a concentration 5 μM in 25 mMHCl (pH 8.0), 50 mM NaCl at 25 °C.