Figure 2.
Circular dichroism spectra in the far-UV (A) and near-UV (B) regions of wild-type (WT) α-sarcin (solid circles) and L145F mutant (open circles). θmrw, mean residue weight ellipticity values in units of degree × cm2 × dmole−1. Fluorescence emission spectra of WT α-sarcin (C) and L145F (D); 1, for excitation at 275 nm; 2 (tryptophan contribution), for excitation at 295 nm and further normalization at wavelengths above 380 nm where the contribution of tyrosine is negligible; 3 (tyrosine contribution), calculated as the difference spectra (spectrum 1 minus spectrum 2). Fluorescence is expressed in arbitrary units considering the intensity at the wavelength of the emission maximum of the WT protein, for excitation at 275 nm, as 1. All the spectra were recorded at 25°C.