Fig. (1) CD spectra of the eL42 species under study. CD spectra at room temperature were obtained using a Jobin Yvon spectrophotometer. Protein concentration was 29 µM except for the eL42-Q51E mutant (16.8 µM). All samples were diluted with 50 mM Tris-HCl buffer (pH 7.6). The α-helix conformation of E. coli bL12 is confirmed by the presence of two negative peaks at 208 and 222 nm.