Figure 6.

The Hsp17.6 aspartate mutants reduced the effect of attenuating oxidant-suppressed growth of E. coli. Five aspartate substitution mutants, D46N (■), D66N (●), D53N (◄), D132N (★), and D44N/46N (▲), were each introduced into E. coli JM109(DE3) via the vector pET28a. The wild-type Hsp17.6 (◯) and empty pET28a (□) were expressed as controls. The E. coli strains were grown in LB broth, and, after 2–2.5 h-incubation, when the OD₆₀₀ reached 0.6–0.8, 0.1 mM IPTG was added to induce the expression of the Hsp17.6 mutants. After 1 h of induction, 2 mM H₂O₂ (A upper panel) or 0.5 mM HClO (B upper panel) were added. Growth was monitored by measurement of the OD₆₀₀. The protein expression was assayed 3 h after the addition of IPTG by western blot using the His-tag antiserum (lower panels of A and B) and visualized by the Tanon-5200 Chemiluminescent Imaging System. Triplicate cultures of each mutant were assayed, and the averages and standard deviations are shown.