TABLE 1.
MICs of different pump substrates from AcrB mutants of E. coli3-AG100
| Mutanta | MIC (μg/ml)b
|
|||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Erythro-mycin | Clarithro-mycin | Azithro-mycin | Clin-damycin | Novobiocin | Levo-floxacin | Moxi-floxacin | Mino-cycline | Chloram-phenicol | EtBr | Pyronin Y | Hoechst 33342 | Linezolid | Oxa-cillin | |
| AcrB-F628F (pseudomutant) | 512 | 512 | 64 | 256 | 512 | 1 | 2 | 4 | 8 | 512 | 32 | 4 | 512 | 512 |
| acrB::rpsLneo | 4 | 4 | 0.5 | 4 | 4 | 0.06 | 0.06 | 0.125 | 1 | 16 | 0.5 | 0.125 | 16 | 0.5 |
| AcrB-615-628MexB | 128 | 64 | 16 | 256 | 512 | 1 | 2 | 2 | 16 | 512 | 16 | 4 | 1,024 | 256 |
| AcrB-615-628MexB-N616G | 256 | 512 | 64 | ND | 512 | 1 | ND | 2 | 8 | 512 | 64 | ND | 1,024 | 256 |
| AcrB-615-628MexB-S623N | 256 | 128 | 16 | ND | 1,024 | 1 | ND | 2 | 16 | 512 | 32 | ND | 1,024 | 512 |
| AcrB-615-628MexB-M626I | 128 | 64 | 8 | ND | 512 | 1 | ND | 4 | 8 | 512 | 32 | ND | 1,024 | 256 |
| AcrB-I626M | 512 | 512 | 32 | ND | 512 | 1 | ND | 4 | 8 | 1,024 | 32 | ND | 512 | 512 |
| AcrB-G616N | 128 | 128 | 16 | ND | 512 | 1 | ND | 4 | 8 | 1,024 | 32 | ND | 512 | 256 |
| AcrB-N623S-Q624S | ND | 512 | ND | ND | 512 | 1 | ND | 4 | 8 | 1,024 | 32 | ND | 512 | 256 |
a
F628F is a pseudomutant with MICs corresponding to wild-type strain 3-AG100, which was generated to demonstrate that the site-directed mutagenesis technique (1, 2) has no inherent effect. AcrB-615-628MexB is a 3-AG100-derived strain where AcrB amino acid residues 615 to 628 were replaced with the homologous MexB residues.
b
MICs that differ ≥fourfold from that ofE. coli3-AG100 are shown in boldface type. ND, not determined.