TABLE 1.

Strains and plasmids used in this study

Strain or plasmid	Description
E. coli strains
BT8	F− Δ(lac)U169 araD139 rpsL thiA relA malT(Con) zhe::Tn10
CC118	araD139 Δ(ara leu)7697 ΔlacX74 phoA20 galE galK thi rpsE rpoB argE(Am) recA1
CC762	Δ(lac)U169 rpsL thi Δ(ara leu)7697 pcnB zad::Tn10 phoR zaj::Tn10kan
CC874	F′ lacIq Δ(lacZ lacY)::cat/araD139 Δ(ara leu)7697 ΔlacX74 phoAΔ20 galE galK thi rpsE rpoB argE(Am) recA1
EM1014	JCFL14 traD(Am)/ΔlacX74 galK his trp lys rpsL λr
Plasmids
pCM389	pBR322-based plasmid carrying wild-type lacY (25)
pCM701	pCM389 carrying a 31-codon insertion in lacY corresponding to residue 38 (25)
PCM702	pCM389 carrying a 31-codon insertion in lacY corresponding to residue 71 (25)
pJFG5	pBR322-derived plasmid carrying tsr (14)
pNLK5	pBAD18-derived plasmid carrying wild-type traD expressed under control of the araBAD promoter
pNLK6	Deletion derivative (SphI-SphI) of pNLK5 encoding approximately the N-terminal 10% of TraD