Figure 5.

Effect of C-terminal mutation on the activity of TfiT, HP0892 and HP0894 toxins. (a) Samples from arabinose-induced cultures of pBAD18-TfiT wildtype and C-terminal mutants or (c) pBAD18-TfiT, pBAD18-HP0892, pBAD18-HP0894 and their respective derivatives either depleted of, or augmented with a C-terminal lysine doublet were taken at intervals for determination of viable counts. (b) Incubation of purified TfiT-His and C-terminal mutant derivatives (1–16 µM) or (d) TfiT-His, HP0892-His, HP0894-His and their respective C-terminal lysine-augmented or depleted derivatives (1–16 µM) with H. pylori recA mRNA (100 ng). Assays in (b,d) used standard reaction buffer (20 mM Tris–HCl pH 7.0, 50 mM NaCl, 2.5 mM MgSO₄) and incubation conditions (37 °C for 30 min). Error bars in (a,c) display standard deviations from three replicates.