Table 1. Summary of the plasmids used in this study.
| Plasmid | Gene | Function of protein | Organism | Reference |
| pNZ(opuAHis) | opuA | Transport of glycine betaine | Lactococcus lactis | [37] |
| pNZ(opuACHis) | opuAC | SBD of OpuA | Lactococcus lactis | [38] |
| pNZ(opuAC-GFPHis) | opuAC-GFP | SBD of OpuA fused to GFP | Lactococcus lactis | This work |
| pNZ(ribUHis) | ribU | Transport of riboflavin | Lactococcus lactis | [39] |
| pNZ(ribCHis) | ribC | Conversion of riboflavin to cofactor (FMN and FAD) | Lactococcus lactis | Laboratory stock |
| pNZ(SBD1&2HisglnP) | glnP(SBD1&2) | SBDs of glutamine transporter GlnPQ | Lactococcus lactis | Laboratory stock |
| pREcLIC(jhp0757His) | jhp0757 | Putative osmoregulatory transporter | Helicobacter pylori | This work |
| pREcLIC(proWXHis) | proWX | Transport of choline | Streptococcus pneumoniae | This work |
| pREcLIC(arpJHis) | arpJ | Function unknown | Listeria monocytogenes | This work |
| pREcLIC(glnPHis) | glnP | Transport of glutamine | Lactococcus lactis | This work |
| pREcLIC(sav1866His) | sav1866 | Multidrug transporter | Staphylococcus aureus | Laboratory stock |
| pREcLIC(bcaP-gfpHis) | bcaP-gfp | Transport of branched chain amino acids | Lactococcus lactis | Laboratory stock |
| pIL252(P32-bcaP-gfp) & pIL253(P32-bcaP-gfp) | bcaP-gfp | Transport of branched chain amino acids | Lactococcus lactis | This work |
| pIL252(P32-bcaP-gfpHis) & pIL253(P32-bcaP-gfpHis) | bcaP-gfp | Transport of branched chain amino acids | Lactococcus lactis | This work |
*NBD, Nucleotide-binding domain; TMD, Transmembrane domain; SBD, Substrate-binding domain.