Table 2.

Phenotypic effects of gradient plate-generated mepA mutations replicated in pK436 and expressed in SA-K2124

Parameter	Value in strain (mutation)a:
	K3486	K3809 (N369Y)	K3811 (M312T)	K4538 (F375V)	K4670 (A161V)	K4842 (S81L)	K4898 (K242E)	K4900 (N308)b	K4902 (F375I)	K4904 (A161T)	K4908 (M391T)	K4984 (M291I)
Selecting conditions applied to SA-K3731		H33342, RD	DQ	EtBr, Pentc	CHX	BAC	TPP	TPP, CHX	EtBr	Pent	DAPI	DAPI
Location of substitutiond		TMS 10	Loop 8-9	TMS 10	TMS 4e	Loop 2-3	TMS 7e	Loop 8-9	TMS 10	TMS 4	TMS 11	TMS 8
Relative susceptibility
BAC	1 (1)	2 (0.5)	2 (0.5)	2 (0.5)	1 (0.25)	2 (0.13)	2 (0.06)	2 (0.06)	2 (0.06)	2 (0.06)	2 (0.06)	2 (0.25)
CHX	1 (1)	1 (0.13)	1 (0.5)	1 (0.25)	1 (0.25)	1 (0.25)	1 (0.25)	1 (0.13)	0.5 (0.13)	1 (0.25)	1 (0.25)	1 (0.25)
DAPI	1 (1)	4 (1)	2 (1)	1 (0.5)	0.5 (0.5)	0.5 (1)	1 (1)	2 (0.5)	4 (1)	1 (1)	2 (1)	2 (1)
DQ	1 (1)	2 (0.5)	2 (0.5)	1 (0.25)	1 (0.25)	1 (0.25)	1 (0.25)	2 (0.5)	1 (0.25)	1 (0.25)	2 (0.5)	1 (0.5)
EtBr	1 (1)	2 (0.5)	2 (0.5)	2 (0.5)	1 (0.5)	2 (0.5)	1 (0.5)	2 (0.5)	2 (0.5)	2 (1)	2 (1)	2 (0.5)
H33342	1 (1)	8 (2)	8 (2)	1 (1)	1 (1)	8 (8)	1 (1)	4 (2)	2 (1)	2 (1)	2 (0.5)	4 (1)
Norfloxacin	1 (1)	4 (2)	4 (1)	0.5 (0.5)	0.5 (0.5)	2 (2)	1 (0.25)	1 (0.5)	1 (0.5)	1 (0.5)	1 (0.5)	1 (0.5)
Pent	1 (1)	4 (2)	4 (2)	2 (1)	1 (0.5)	2 (0.5)	2 (0.5)	2 (0.25)	2 (0.25)	1 (1)	2 (0.25)	2 (0.25)
RD	1(1)	2(2)	2(2)	1(1)	1(1)	1(2)	0.5(0.5)	0.5(0.5)	0.5(0.5)	1(0.5)	1(0.5)	1(1)
	0
TPP	1(1)	2(0.25)	2(0.25)	2(0.5)	2(0.5)	2(0.13)	2(0.25)	1(0.25)	1(0.25)	1(0.25)	2(0.25)	2(0.5)
1 (1)EtBr efflux (%) ± SD	27.2 ± 4.6	82.2 ± 0.4	83.1 ± 0.6	56.0 ± 5.8	40.4 ± 3.0	80.4 ± 2.2	52.9 ± 2.8	63.0 ± 2.0	66.4 ± 4.7	38.4 ± 5.7	60.3 ± 13.0	36.2 ± 6.6
% Changef		202	206	106	49	196	94	132	144	41	122	33
P value		<0.001	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001	0.001
IC50 for EtBr efflux (reserpine/paroxetine)		3/1.8	5.2/2.7	3/2.6	4.6/3.6	3.8/>4.5	2.4/1.5	2.4/2.2	1.8/2.5	3.2/1.8	1/0.8	0.6/0.5

^aSusceptibility, fold reduction in MIC in the presence of 20 μg/ml reserpine (in parentheses), and IC₅₀ data were normalized to K3486, in which wild-type mepA is expressed.

^bMutation consisted of duplication of indicated residue.

^cPent, pentamidine.

^dPredicted by SOSUI. Loop x-y, extramembrane loop connecting TMSs x and y (Fig. 1 shows details).

^eAlternate location predicted by TMHMM algorithm. See the text for details.

^fCompared to K3486.