Figure 1

Proposed structural model of B. burgdorferi BamA. A. The predicted structure of the B. burgdorferi BamA protein (left) determined using the I-TASSER algorithm [68-70] compared to the structure of BamA from N. gonorrhoeae (right). Predicted β-sheet regions are depicted in yellow and α-helical regions are depicted in red. B. Diagram of the β-barrel domain of the B. burgdorferi BamA protein with predicted extracellular loops numbered. The location of the c-Myc tag (EQKLISEEDL) insertion site in extracellular loop three is indicated in green. The site of the predicted α-helical region in extracellular loop four is indicated in red and the blue region within extracellular loop six indicates the position of the conserved RGF motif. OM; outer membrane. C. The c-Myc tag inserted in predicted loop three (BamA::c-Myc) was examined using surface immunofluorescence assays and antibodies to c-Myc or the periplasmic FlaB protein (top; two leftmost panels). The DNA-specific dye DAPI was also used to identify all organisms in a given microscopic field (top; third panel from left). As a control for the surface specificity, organisms also were fixed to slides before incubation with the c-Myc and FlaB antibodies (fixed panels). The parental, wildtype strain was also subjected to the same assays (bottom panels).