| Escherichia coli is the leading cause of urinary tract infections (UTI) and pregnant women with UTIs are at increased risk of developing pregnancy-related complications such as pyelonephritis. The Dr adhesin, used by uropathogenic E. coli to tether to tissues of the urogenital tract, is comprised of subunits of the DraE protein. The DraE adhesin binds to the mammalian receptor decay-accelerating factor (DAF) but the interaction is not completely understood. Ten recombinant E. coli mutants, each with an amino acid residue of the hydrophilic domain VI of the DraE adhesin mutated to alanine via mutagenesis, were assayed for binding and invasion capabilities to recombinant Chinese hamster ovary cells expressing DAF. Three mutations - T123A, T125A(2), and Y130A- were found to cause two-fold lower binding and invasion outcomes where mutant G I28A provided a two-fold decrease in binding compared to wild type. The substitutions suggest binding and invasion phenotypes of the DraE adhesin can be separated and amino acids T123, T125, G128 and Y130, constitute part of the complex conformational 3-D epitope for DraE recognition of DAF. |
