The Effect of Lipopolysaccharide Core Structure Defects on Transformation Efficiency in Isogenic Escherichia coli BW25113 rfaG, rfaP, and rfaC Mutants

Abstract

The role of lipopolysaccharide core components in DNA permeability of Escherichia coli was studied. The K-12 BW25113 wild type strain and its derivatives containing deeprough mutations of rfaG, rfaP, and rfaC, which are defective in terms of lipopolysaccharide core structure, were assessed for DNA permeability using heat shock transformation. Outer membrane stability was also assessed through antibiotic and detergent sensitivity tests. Although the minimum inhibitory concentrations for novobiocin and sodium dodecyl sulfate adhered to the expected observations of rfaC being more sensitive than rfaP, then rfaG, and wild type, the transformation frequencies showed the unexpected results of rfaC, rfaP, wild type, and rfaG in the order of highest to lowest. Both the polysaccharide chain and phosphorylation of the lipopolysaccharide core were found to affect outer membrane permeability to small molecules and DNA.