TABLE 3.

The inhibitory zone determined by the disc diffusion method for mtrE mutants expressed with or without mtrC or mtrCD in E.coli (ΔtolC) TG1(DE3) and (ΔacrB) KAM3(DE3) cells

The inhibitory zone diameter is given in mm; abbreviations are NI, no inhibition of growth; NG, no growth due to complete growth inhibition; Naf, nafcillin; Tet, tetracycline; Ery, erythromycin; Nov, novobiocin; and Van, vancomycin. The MtrE derivatives with intra-protomer groove mutations are shown in bold.

Strain/constructs	Naf (1 μg/ml)	Tet (30 μg/ml)	Ery (10 μg/ml)	Nov (5 μg/ml)	Van (30 μg/ml)
TG1/pACYC	20	35	31	27	NI
TG1/MtrE WT-CD	12	25	20	19	NI
TG1/MtrE N198L-CD	20	33	31	27	7
TG1/MtrE E434K-CD	25	40	33	28	NG
TG1/MtrE Q441E-CD	19	40	33	27	NG
TG1/MtrE R239E-CD	14	29	27	25	NI
TG1/MtrE K397E-CD	14	29	29	21	NI
KAM3/pET21a	7	30	26	20	NI
KAM3/MtrE WT	NI	26	21	15	NI
KAM3/MtrE N198L	NI	26	21	15	NI
KAM3/MtrE E434K	NI	26	21	15	NI
KAM3/MtrE Q441E	NI	26	21	15	NI
KAM3/MtrE R239E	NI	26	21	15	NI
KAM3/MtrE K397E	NI	26	21	15	NI
KAM3 pACYC	7	36	31	17	NI
KAM3/MtrE WT-C	24	36	37	21	9
KAM3/MtrE N198L-C	NI	26	21	15	NI
KAM3/MtrE E434K-C	NG	50	40	NG	NG
KAM3/MtrE Q441E-C	NG	36	37	21	27
KAM3/MtrE E434K-CD	20	46	40	19	20
KAM3/MtrE WT-CD	NI	27	21	10	NI