Table 1.
σ70 R4 substitution | Epistasis between alanine substitutions of σ70 R4 and alanine substitutions of the class II PC surface of Rob and SoxS at two promoters
|
|||
---|---|---|---|---|
fumC promoter
|
micF promoter
|
|||
Rob | SoxS | Rob | SoxS | |
K593A | None | D75A, M78A | N.A. | M78A, D79A |
R596A | N.A. | None | N.A. | None |
R599A | D75A | D75A | N.A. | None |
R603A | N.A. | None | D75A | D75A, D79A |
All amino acids of σ70 R4 that confer a defect in Rob-dependent transcription activation (Fig. 1) or SoxS-dependent transcription activation12 of the fumC and/or micF promoters when substituted with alanine are listed even if no interacting partners have been identified. The alanine substitutions within the class II PC surface of Rob (Figs. 5 and 6) and SoxS12 that are epistatic partners of the listed alanine substitutions of σ70 R4 are shown according to the promoter at which the epistasis was observed. N.A., not applicable because this substitution of σ70 R4 has no effect on the activity of the activator; none, no epistasis occurs between these combinations of the activator and the σ70 R4 substitutions.