Table 1. Sensitivity of mutant RNAP holoenzymes to AsiA.

σ70 mutant	Sensitivity of σ70-containing holoenzyme to AsiA in vitro
Wild type	+ + + +
F563Y*	+
R541C†	≥ + + + +
L607P	≥ + + + +
R541C/L607P	≥ + + + +
F563Y/R541C	+ +
F563Y/L607P	≥ + + + +
F563Y/R541C/L607P	≥ + + + +

^*Boldface indicates that the F563Y substitution disrupts the interaction of σ⁷⁰ region 4 with AsiA (but not with the β-flap).

^†Italics indicate that the designated substitutions disrupt the interaction of σ⁷⁰ region 4 with the β-flap (but not with AsiA).