Browsing by Author "Pushpker, Rajnigandha"

Now showing 1 - 1 of 1
  • Thumbnail Image
    ItemOpen Access
    Evaluation of Genes for Escherichia coli Envelope Proteins for their Participation with the Small Multidrug Resistance Protein, EmrE, Mediated pH/Osmotic Tolerance
    (2017) Pushpker, Rajnigandha; Turner, Raymond; Storey, Douglas; Hynes, Michael; Schryvers, Anthony
    The small multidrug resistance (SMR) protein, EmrE transports quaternary cationic compounds (QCC) across the cytoplasmic membrane in the Gram-negative bacterium Escherichia coli. EmrE over-expression results in the reduction of host pH and osmotic tolerance, likely through EmrE-mediated biological QCC based osmoprotectant efflux. It is not known how the substrates translocated by EmrE into the periplasmic space escape across the outer membrane (OM). The observation that an OM protein, OmpW, participates in EmrE-mediated substrate efflux provided the hypothesis that additional OM and periplasmic proteins participate in the process. By conducting alkaline pH based growth phenotype screens I identified 10 additional proteins that may contribute to the EmrE-mediated osmoprotectant efflux: GspD, HofQ, YccZ, AcrA, EmrA, EmrB, ProX, OsmF, DcrB and YggM. Further screening of these using a hyperosmotic stress ± betaine growth phenotype assay identified OmpW and two periplasmic proteins, DcrB and YggM, to have involvement in the EmrE-mediated export of betaine.