Table 1.

Strains used in this study

E. coli strain	Description	Reference or source
K-12 MG1655	λ− F− ilvG rfb-50 rph-1	Blattner et al. (28)
ATCC 21277	K-12 supE relA+ Kmr-Ptac-thrA*BC ilvA422	Shiio et al. (29)
BL21(DE3)	F− ompT hsdSB(rB−, mB−) gal dcm(DE3)	Invitrogen
MG-105	K-12 MG1655 Ptac-thrA*BC ΔlacI Δtdh ΔtdcC::rhtA23 ΔsstT::rhtA23	Lee et al. (30)
MG-105E	MG-105(pET16tac-thrABC)	This study
MG-105ES	MG-105(pET16tac-thrABC)(pSC-4)	This study