FIG. 3.

Partial rescue of impaired AR2 by amino acid substitutions in αNTD (RpoA). All strains carried a low-copy-number plasmid with the simple FNR-activated class II promoter, FF(−41.5), fused to lacZ (32) and plasmid pBR322-encoded wild-type FNR or FNR-K49E. In addition, RpoA or the indicated variants were supplied on plasmids (Table 1) encoding wild-type E165, A165, or K165. All cultures were grown under anaerobic conditions in L broth supplemented with glucose (0.2%) at 37°C for 16 h. β-Galactosidase activity was measured in at least three independent cultures of each strain.