TABLE 2.

Expression of ylmA-lacZ fusions^a

Strain	Relevant genotype^b	Fusion genotype	Addition to medium (no. of aa)	β-Galactosidase activity
Strain	Relevant genotype^b	Fusion genotype	Addition to medium (no. of aa)	MU	%^c
BB2718	Wild type	ylmAp⁺	None	7.5	35
			13	2.8	13
			16	0.22	0.9
BB2724	codY		None	20.2	94
			16	21.6	100
BB2729	Wild type	ylmAp1	None	0.04	<0.2^d
			13	0.04	<0.2
			16	0.03	<0.2
BB2733	codY		16	17.7	100
BB2730	Wild type	ylmAp2	None	25.2	90
			13	20.9	75
			16	9.8	35
BB2734	codY		16	27.9	100

↵a Cells were grown in TSS glucose-ammonium medium with or without a mixture of 13 aa or 13 aa and ILV (16 aa) (see Materials and Methods). 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 not exceed 30%.
↵b All strains contained a lacA null mutation that eliminated endogenous β-galactosidase activity (9).
↵c β-Galactosidase activity of each fusion in the 16-aa-containing medium in a strain containing a codY null mutation was normalized to 100%.
↵d β-Galactosidase activity was similar to the background activity in a strain without a lacZ fusion.