TABLE 1.
Bacterial strains and plasmids used in this study
| Strain or plasmid | Genotype or descriptiona | Source or reference |
|---|---|---|
| S. Typhimurium | ||
| 14028 | Wild type | ATCC |
| ΔcpxR mutant | 14028 ΔcpxR::Kmr | 51 |
| ΔcpxA mutant | 14028 ΔcpxA::Kmr | 51 |
| ΔcpxRA mutant | 14028 ΔcpxRA::Kmr | 51 |
| Δ(ackA-pta) mutant | 14028 Δ(ackA-pta)::Kmr | 51 |
| ΔcpxA Δ(ackA-pta) mutant | 14028 ΔcpxA::FRT Δ(ackA-pta)::Kmr | 51 |
| E. coli | ||
| DH5α | E. coli K-12 laboratory strain | Invitrogen |
| BL21(DE3) | Strain for expression of recombinant proteins | Invitrogen |
| Plasmids | ||
| pCA24N | High-copy-number cloning vector, lac promoter; lacIq Cmr | 80 |
| pCA-NlpE | pCA24N derivative expressing E. coli K-12 NlpE from the lac promoter | 80 |
| pKK232-8 | pBR322 derivative containing a promoterless chloramphenicol acetyltransferase (cat) gene; Apr | 81 |
| pcpxRA-cat | pKK232-8 derivative containing a cpxRA-cat transcriptional fusion from nucleotides −544 to +57 | 51 |
| pssrAB-cat-302/+478 | pKK232-8 derivative containing a ssrAB-cat transcriptional fusion from nucleotides −302 to +478 | 29 |
| pssrAB-cat-208 | ssrAB-cat transcriptional fusion from nucleotides −208 to +478 | 29 |
| pssrAB-cat-106 | ssrAB-cat transcriptional fusion from nucleotides −106 to +478 | 29 |
| pssrAB-cat-55 | ssrAB-cat transcriptional fusion from nucleotides −55 to +478 | 29 |
| pssrAB-cat+336 | ssrAB-cat transcriptional fusion from nucleotides −302 to +336 | 29 |
| pssrAB-cat+240 | ssrAB-cat transcriptional fusion from nucleotides −302 to +240 | 29 |
| pssrAB-cat+119 | ssrAB-cat transcriptional fusion from nucleotides −302 to +119 | 29 |
| pssrAB-cat+69 | ssrAB-cat transcriptional fusion from nucleotides −302 to +69 | 29 |
| pssrAB-cat+10 | ssrAB-cat transcriptional fusion from nucleotides −302 to +10 | 29 |
| pssaG1-cat | pKK232-8 derivative containing an ssaG-cat transcriptional fusion from nucleotides −232 to +361 | 15 |
| pQE80 | Vector for expression of His-tagged protein; Apr | Qiagen |
| pQE80cpxR | N-terminal His6-CpxR overexpression plasmid; Apr | 79 |
a
The coordinates for the cat fusions are indicated with respect to the transcriptional start site for each gene. Apr, ampicillin resistance; Cmr, chloramphenicol resistance; Kmr, kanamycin resistance.