Figure 3

Biophysical characterization by (a) intrinsic tryptophan fluorescence (ITF) and (b) Far UV CD. For ITF measurements the 0.01 mg/ml of F₁, F₂, DF₁ (CFSE/AF610 conjugated), ^FA+F₂ (Folic acid conjugated), and F₂^dox+ (doxorubicin conjugated) capsid proteins were excited at 292 nm and emission was recorded from 300 to 400 nm. The protein spectra for the capsid proteins were found near 340 nm, which confirmed the folded state of proteins. The Far UV CD spectra of F₁ and F₂ as well as ligands conjugated (DF₁, ^FA+F₂, and F₂^dox+) capsid proteins (0.10 mg/ml) were taken from 190 to 260 nm at ambient temperature. The CD spectra with the negative ellipticity at 208 nm and positive peak below 200 nm suggested the folded structure of the proteins.