Table 2.

Effects of modifications within the lysP promoter/control region on lysP expression^a

E. coli strain or strain carrying plasmid	Description of modification within the lysP promoter/control region	Induction of lysP upon lysine limitation (lysPno lysine/lysP10 mM lysine)b
MG-LR	None	7.90
MG1655-ΔlacZ/pRSlysP	None	3.43
MG-LR4	Deletion of T-N11-A motif (nucleotides −83 to −52)	1.03
MG1655-ΔlacZ/pRSlysP0	Deletion of T-N11-A motif (nucleotides −88 to −53)	1.28
MG1655-ΔlacZ/pRSlysP1	Replacement of A/C at position −53	2.77
MG1655-ΔlacZ/pRSlysP2	Replacement of T/G at position −65	1.85
MG1655-ΔlacZ/pRSlysP3	Replacement of A/C (position −53) and T/G (position −65)	1.24

^aStrains were grown aerobically in glucose minimal medium in the absence or presence of 10 mM lysine to an OD₆₀₀ of ∼0.8. β-Galactosidase activity was determined and served as a measurement for lysP expression.

^bThe ratio between lysP expression levels in the absence and presence of lysine indicates the inducibility of the lysP promoter. Data were obtained from at least three independent experiments, and average values (the standard deviation was about 15%) were used for calculating the ratios.