Table 1.

Expression of ybgE-lacZ fusions^a

Strain	Relevant genotype b	Fusion genotype	Additions β to the medium	-galactosidase activity (MU)	β-galactosidase activity (%)c
BB2770	wild-type	ybgE292p+ (sites Ia, I, II)	none	19.2	4.5
			ILV	3.49	0.8
			13 aa	11.7	2.7
			16 aa	1.12	0.3
BB2771	codY		none	268.0
			16 aa	428.0	100
BB3301	wild-type	ybgE292p1down	none	42.3	6.2
			ILV	14.8	2.2
			13 aa	38.9	5.7
			16 aa	13.5	2.0
BB3302	codY		none	420.0
			16 aa	681.0	100
BB3400	wild-type	ybgE292p1down/11up	none	10.2	1.5
			16 aa	2.52	0.4
BB3415	codY		none	326.0
			16 aa	648.0	100
BB2808	wild-type	ybgE190p+ (sites Ia, I)	none	78.0	80
			ILV	48.2	49
			13 aa	51.3	52
			16 aa	16.5	17
BB2818	codY		none	86.2
			16 aa	97.8	100
BB3277	wild-type	ybgE190p1up	16 aa	101.0	93
BB3278	codY		16 aa	109.0	100
BB2806	wild-type	ybgE182p+ (sites I, II)	none	1.90	2.2
			ILV	0.31	0.4
			13 aa	1.24	1.4
			16 aa	0.14	0.2
BB2816	codY		none	50.1
			16 aa	87.5	100
BB2807	wild-type	ybgE80p+ (site I)	none	12.7	68
			ILV	7.59	41
			13 aa	8.85	47
			16 aa	2.40	13
BB2817	codY		none	14.6
			16 aa	18.7	100
BB3026	wild-type	ybgE162 (site Ia)	none	204.0	121
			16 aa	199.0	118
BB3028	codY		none	176.0
			16 aa	169.0	100

^aCells were grown in TSS glucose-ammonium medium with or without a mixture of 16 amino acids (aa) or the same mixture without ILV (13 aa) or ILV only. β-Galactosidase activity was assayed and expressed in Miller units (MU). All values are averages of at least two experiments, and the mean errors did notexceed 30%.

^bStrain BB2511 and all its derivatives have very low endogenous β-galactosidase activity due to a null mutation in the lacA gene ⁵⁶.

^cβ-Galactosidase activity of each fusion in the 16 aa-containing medium in a strain containing a codY null mutation was normalized to 100%.