TABLE 1.

Activity of selected MarA mutants at repressed and activated promoters^a

Role of residue	MarA mutation	% Repression			% Activation
		Type 1		Type 2	Class I			Class II
		purA	hdeA	rob	fpr	mar	zwf	fumC	inaAb	micF
Binds αCTD	Trp19Ala	10	40	30	0	—	5c	5c	—	10
Relatively activation	Arg36Ala	95	>100	110	—	—	35	—	50	—
specific	Thr12Ala	90	95	85	15	45	15	15	30	30
	Thr95Ile	70	50	70	0	50	10	−10	5	0
	Pro106Ala	40	55	25	0	5	0	0	—	0

^aAssays were performed in duplicate or triplicate (see Materials and Methods) except where noted. Values (±10%) are given to the nearest 5% and are normalized to the results for wild-type MarA as 100% repression or activation. Specifically, the percent repression by a MarA protein is determined by the equation [(P − M)/P]100 and the percent activation by a MarA protein is determined by the equation [(M − P)/P]100, where P and M are the LacZ activities of cells containing pMPM9 (completely inactive MarA control) and the MarA protein in question, respectively. Finally, the values in the table were obtained by normalizing the percent for a MarA mutant to that of wild-type MarA, set as 100%. —, not determined.

^bOne experiment, two points.

^cTwo experiments, one point each; negative control has plasmid pMPM-T6Ω instead of pMPM9.