Complementation of ompF Into ΔompCΔompF Escherichia coli Confers Increased Sensitivity To SDS-EDTA Treatment

SUMMARY The outer membrane (OM) of gram negative bacteria contributes to inherent antibiotic resistance as well as protection against toxins. OM general diffusion porins, such as OmpC and OmpF, regulate movement of biomolecules in and out of the periplasm, preventing large and potentially harmful molecules from entering the bacteria. OmpC has also been shown to contribute to membrane asymmetry through the Mla pathway. Previous studies have found E. coli deficient of OmpC are sensitive to treatment with detergent sodium dodecyl sulfate (SDS) and ethylenediaminetetraacetic acid (EDTA) when compared to wild type. In contrast, double deletions of OmpC and OmpF (△ompC△ompF) show comparable resistance to wild-type (WT) E. coli. Further studies into single ompF deletions have shown no appreciable difference in sensitivity to SDS-EDTA from wild-type. Here, we hypothesize expression of ompF in the absence of ompC will result in sensitivity towards SDS-EDTA. To test this, we transformed a vector containing ompF into △ompC△ompF mutants, then compared their relative sensitivity to WT and △ompC mutants over increasing EDTA concentrations. Our study found complementation of ompF back into △ompC△ompF mutants induced an increased SDS-EDTA sensitivity. Our results implicate a dynamic relationship between OmpF and OmpC, where presence of OmpC and expression of ompF may influence OM stability.