FIG. 2.

Analysis of the secondary structure by far-UV circular dicroism. Far-UV circular dicroism spectra at 4 to 50°C for pure EstRB8 from E. coli bearing pBK1CpnEst grown at 4°C (•), 20°C (○), 30°C (▾), or 37°C (▿) were recorded, and the relative ellipticity at 220 nm was measured. The conditions used are described in Materials and Methods. The ellipticity at 220 nm obtained with the EstRB8 produced in E. coli grown at 4°C was assumed to be 100%. The three sets of data corresponding to EstRB8 purified from E. coli expressing plasmid pBK1CpnEst or pBK1Est at 20, 30, and 37°C were statistically equivalent, and only the data for pBK1CpnEst are shown.