TABLE 2.

Binding to W-box DNAs with and without T-to-U base substitutions

Position of substitution	KAa	Decrease
	m−1	-fold
No substitution	(1.9 ± 0.4) ×107
T5 to U	(1.7 ± 0.1) ×107	1.1
T6 to U	(1.8 ± 0.3) ×106	11
T7 to U	(8.4 ± 0.3) ×106	2.3
T9′ to U	(7.5 ± 2.5) ×105	25
T12′ to U	(1.7 ± 0.1) ×107	1.1

^a S.D. values in four repeated experiments were used as error levels.