FIG. 5.

Topology analyses of the ComB6 subunit of the H. pylori transformation competence-mediating type IV transport system. (A) The computer programs listed at left predicted the transmembrane segments shown as solid rectangles with residue numbers relative to the N terminus. Solid rectangles identify transmembrane segments supported by results of reporter protein fusion studies; shaded rectangles are not supported by experimental data. *, amino acid (aa) positions of the PhoA or GFP fusions represented in panel B. Kyte-Doolittle hydrophobicity blot of HP0037: SP, signal peptide; TMS1 to TMS5, transmembrane segments 1 to 5; CP, cytoplasmic location; PP, periplasmic location. (B) Reporter protein activity levels of E. coli CC118 (phoA) or XL1-Blue (gfp) expressing six defined fragments of comB6 translationally fused to phoA (above the x axis) or gfp (below). Numbers at the bottom refer to the fusion site of the corresponding ComB fusion protein tested. Reporter protein activities represent the average of at least three experiments, with standard deviations indicated.