Table 4. The in vivo effect of mutations at the aperture tip region of MdsC^a in the presence of wild type MdsA and MdsB^a.

Background	ATCC14028SΔacrABΔmdsABC::Cm5ΔtolC::Tn10
MdsC protein	MIC (µg/mL)b
	Crystal violet	Methylene blue	Acriflavine	Rhodamine 6G	Vancomycinc
Noned	4	32	16	4	800
MdsC-WT	16	256	32	64	700
MdsC-G220A	4	32	16	4	500
MdsC-G433A	4	32	16	4	600
MdsC-L441R	4	32	16	4	700

^aThe in vivo effect of mutations in the aperture tip region of MdsC was determined by measuring the resistance of the ATCC14028SΔacrABΔmdsABC::Cm5ΔtolC::Tn10 strain to several substrates. MdsC and its variants were expressed from pMdsABC2, pMdsABC2 MdsC-G220A, pMdsABC2 MdsC-G433A, pMdsABC2 MdsC-L441R.

^bAll MIC measurements were done in triplicate. The concentrations of crystal violet and acriflavine used to determine the MICs were 0, 1, 2, 4, 8, 16, and 32 µg/mL. The concentrations of rhodamine 6G and methylene blue used to determine the MICs were 0, 4, 8, 16, 32, 64, 128, and 256 µg/mL.

^cThe vancomycin concentrations used to determine the MICs were 0, 300, 400, 500, 600, 700, and 800 µg/mL.

^dNone, strain carrying the empty vector pKAN6B instead of a pMdsABC2 variant.