Table 2.

Biophysical parameters of proteins

Protein*	Tm, °C	ΔG,† kcal/mol	Molecular mass, Da
His-Csp	59.8	3.6	8,565
His-Csp/2‡	No expression		5,854
His-1b11	57.1	2.0	10,722
His-1c2	54.8	5.3	10,972
His-1g6	48.4	2.4	10,485
His-2f3	61.4	1.8	10,582

^*The sequences of the chimeric proteins are as described in Table 1 with appended tags MRGSHHHHGSR (N terminus) and AQAEA (C terminus). 

^† The conformational stability ΔG at a temperature T was calculated by using the Gibbs–Helmholtz equation ΔG(T) = ΔH_m(1 − T/T_m) − ΔC_p [(T_m − T) + ln(T/T_m)], while inferring the midpoint of thermal unfolding (T_m) and the enthalpy change for unfolding (ΔH_m) at the T_m from the denaturation curve (30) and assuming for ΔC_p (the difference in heat capacity between unfolded and folded conformation at constant pressure) a value of 12 cal per residue (40). 

^‡ The His-Csp/2 protein, which comprises the N-terminal half of CspA (LQSGKMTGIV KWFNADKGFG FITPDDGSKD VFVHFSAW) plus the terminal tags, was found in neither the soluble nor the insoluble fraction of the cytoplasm and is presumed to have been degraded within the cell.