FIG 1.
Construction of H. pylori G27 strains expressing Tat-EGFP. The coding sequences for Tat signal peptide (SP)-EGFP fusion proteins (HydA-Tat-EGFP, KapA-Tat-EGFP, KapA-ΔTat-EGFP, and TorA-Tat-EGFP) followed by a chloramphenicol resistance cassette were integrated into the H. pylori G27 genome downstream of the cagA promoter (PcagA) via allelic-exchange recombination. The signal peptide sequences with the twin-arginine motif [the two arginines are shown in boldface type, and the consensus sequence (S/T)RRXFLK is underlined] for HydA and KapA from H. pylori were identified by the PRED-TAT, TATFIND, and TatP prediction programs (33), and the signal sequence for TorA from E. coli was used in a study reported previously (32). In the KapA-ΔTat-EGFP signal peptide, the twin-arginine motif was deleted.