Figure 2
Spectroscopic evaluation of molecular interaction between αS and EGCG with intrinsic fluorescence, CD spectroscopy, and FTIR spectroscopy. (A) Dissociation constant between αS and EGCG assessed with the intrinsic fluorescence of tyrosine residues of αS. Differences in the tyrosine intrinsic fluorescence emitted at 308 nm in the presence (Ii) and absence (Io) of EGCG were plotted as a function of EGCG concentration. Dissociation constant (Kd) of 100 μM was calculated from a double-reciprocal plot of the saturation curve (Inset). (B) Circular dichroism (CD) spectra of the amyloid fibrils of αS prepared without (black dots) and with (red dots) EGCG following co-incubation for 130 hr at 37 °C with agitation. (C) FTIR spectra and their second derivative spectra of the amyloid fibrils of αS prepared without (left) and with (right) EGCG after 96hr incubation at 37 °C with agitation. The FTIR absorption spectra have been deconvolved according to the peaks found in the second derivative spectra.
