TABLE 8.

Synergistic effects of CRP, α-CTD, and RhaR at rhaSR

Activator and combinations	No. of activators	Results at promoter fusion:
		Φ(rhaS-lacZ)Δ128		Φ(rhaS-lacZ)Δ216
		Fold activationa	Synergistic effectb	Fold activationa	Synergistic effectb
RhaR
−CRP − α-CTD	1	4.3		4.3
+CRP − α-CTD	2	83	19	162	37
−CRP + α-CTD	2	72	17	72	17
+CRP + α-CTD	3	18	4.2	118	27
α-CTD
−CRP − RhaR	1	0.78		0.78
+CRP − RhaR	2	13	17	2.6	3.3
−CRP + RhaR	2	13	17	13	17
+CRP + RhaR	3	2.9	3.7	1.9	2.4
CRP
− α-CTD − RhaR	1	20		13
+ α-CTD − RhaR	2	340	17	41	3.2
− α-CTD + RhaR	2	380	19	470	36
+ α-CTD + RhaR	3	84	4.2	68	5.2

^aFor each set, the fold activation by the activator on the first line of the set is defined as the fold increase in expression in the presence of that activator versus the absence of that activator. This fold activation was calculated for each combination of the other two activators. 

^bSynergistic effect represents the fold activation by a given activator in the presence of one or both other activators divided by the fold activation by that activator when alone.