Fluorescence characterization of wt and Arg173Pro forms at pH 7.4 and 5.0.

a Stern-Volmer constant for the quenching of Trp residues by acrylamide.
b Free energy change of unfolding and
c concentration at which half of the protein is unfolded, respectively, calculated from equilibrium unfolding curves, as described previously [18] and shown in Fig 2. N/A, not assayed
d Light scattering of proteins (0.2 mg/mL) measured after 48 h incubation at 37°C with excitation and emission wavelengths set at 350 nm.
e Fluorescence resonance energy transfer efficiency (E), calculated from Eq (2). FDA and FD are the intensity of Trp emission in the presence and in the absence of the acceptor molecule bis-ANS (excitation set at 295 nm and emission at 335 nm).
f Intensity ratio of the fluorescence associated to bis-ANS and Trp in the samples described above, measured by direct excitation of each dye, as described in ‘Methods’.
Fluorescence characterization of wt and Arg173Pro forms at pH 7.4 and 5.0.