Table 1.

DNA-binding affinities of WT S. pneumoniae SifR for duplexes harboring DNA O/P sequences^a

Locus tag or gene name O/P	Ka (×108) (M−1)b
catE (spd_0072)	WT: 1.0 (±0.2); C84S: 4.8 (±1.5)
ywnB (spd_1440)	3.2 (±0.4)
yhdA (spd_1375)	0.23 (±0.04)
fre (spd_0527)	0.25 (±0.05)
trxB (spd_1275)	0.13 (±0.04)

^aSequence of the core operator regions shown in Figure 4A (see Table S4 for complete sequences of the dsDNAs used here), with DNA-binding data shown in Figure 4.

^bUpper limit for this competition assay under these conditions is 0.1 × 10⁸ M⁻¹. Conditions: 25 mM Tris–HCl, 150 mM NaCl, pH 7.4, 25.0 °C.