Table 1.

Summary of DNA binding parameters for SpCstR and SmCstR^a

Protein	Treatmentb	DNA operator	K tet (M−1)
C9A SpCstR	None	S. mitis cst	2.2 ± 0.2 × 108
SmCstR	None	S. mitis cst	1.4 ± 0.2 × 108
C9A SpCstR	None	Sp adcA	4.9 ± 0.1 × 105
C9A SpCstR	Tetrathionate	S. mitis cst	<3.0 × 105
SmCstR	CysSSH	S. mitis cst	<6.3 × 105

^aConditions: 10 nM cst operator dsDNA in 25 mM Tris–HCl, 200 mM NaCl, 2 mM EDTA, 2 mM TCEP, pH 8.0, 25.0ºC. The DNA binding data were fit to a two-tetramer DNA binding model (see Materials and Methods) and reflect the results of triplicate titrations. ^bNone, dithiol-reduced protein.