Table 1. Structure–activity comparisons of flavones on RepA ATPase activity.

Flavones	Substitutions								Residual ATPase activity (percentage of control)
	3	5	7	8	2′	3′	4′	5′
Reactions were performed in buffer A as described in the Materials and Methods using 80 nM RepA protein, 100 nM (dT)20 800 µM ATP and 250 µM of the flavone compounds (dimyricetin 50 µM) in buffer A. ATPase activity is expressed relative to activity without inhibitor. OCH3 indicates methoxy substitutions.
Apigenin			OH				OH	OH	>95
Galangin	OH	OH	OH						>95
Luteolin		OH	OH			OH	OH		5
Hydroxyflavonea			OH	OH		OH	OH		50
Morin	OH	OH	OH		OH		OH		5
Quercetin	OH	OH	OH			OH	OH		>90
Trimethyletherb	OH	OH	OH			OCH3	OCH3	OCH3	>95
Myricetin	OH	OH	OH			OH	OH	OH	10
Dimyricetin	OH	OH	OH			OH	OH	OH	2

^a3′,4′,7,8-Tetrahydroxyflavone.

^bMyricetin trimethylether.