Fig. 3
Large-scale structural re-arrangements within the native ensemble. a QY of W67 as a function of temperature at 14.5 mM (blue), 43 mM (gray), 90 mM (cyan), 170 mM (green), and 500 mM IS (red). The QY at 6 M urea is shown as a reference (black). Note the large changes in QY even at the lowest temperatures where unfolded population is negligible. b Longer and shorter fluorescence lifetimes of W67 as circles and diamonds, respectively. The color code is the same as in panel a. The filled gray symbols represent the life-times of tryptophan in the reference peptide C-pep. c The relative amplitudes following the same color code as in b. The vertical lines indicate the inflection points. d Difference in melting temperatures between far-UV CD and W67 life-time amplitudes calculated as Tm (CD) – Tm (Life-time). e QY of the Cnu upon excitation at 274 nm exhibiting similar characteristics as that of QY295 and following the same color code as in panel a. (Inset) Spectral deconvolution of temperature-wavelength data shows two components, the first of which accounts for the average spectrum (U1) and the second represents an anti-correlation between tryptophan and tyrosine fluorescence emission bands (U2). f The amplitude of U2 following the color code as in panel a. g A pictorial representation of the conformational events monitored by the data shown in panel f with a large structural heterogeneity at low IS that decreases continuously with increase in the salt concentration. Source data are provided as a Source Data file
