Table 2.

Stimulation of OmpR phosphorylation by C1 DNA: Comparison of phosphodonors

Phosphodonor	OmpR-P, percentage of total
	−C1	+C1	Fold stimulation
Acetyl phosphate	49	84	1.7
MBP-EnvZ	10	21	2.1
	11	78	7.1
EnvZ115	14	37	2.6
	12	56	4.7

OmpR (3.3 μM) is phosphorylated by acetyl phosphate (top row); by 8.8 μM OmpR and 1 μM MBP-EnvZ (second row); by 3.3 μM OmpR and 1 μM MBP-EnvZ (third row); by 5 μM OmpR with 30 μM of the truncated EnvZ protein EnvZ115 (fourth row); or by 44 μM EnvZ115 (bottom row), as described in Materials and Methods. OmpR-P is expressed as a percentage of the total OmpR protein present in the reaction, as determined by reverse-phase HPLC on a C4 column in the absence of C1 DNA (−C1) and in the presence of a 2-fold molar excess of C1 DNA (+C1). The degree of stimulation by C1 DNA is listed in the third column. The values shown in the table represent the means of duplicate samples, and the variation among duplicates was less than 10%.