TABLE 1.

Modulation of adenylyl cyclase activity by the phosphorylation state of IIA^Glca

Nature of crr allele	Adenylyl cyclase activity (pmol of cAMP formed/min/mg of protein) with addition:
	None	K.Pi	K.Pi + α-MG
crr deletion	58 ± 10	101 ± 4	59 ± 7
WT crr	109 ± 9	530 ± 60	90 ± 36
H75Q crr	108 ± 15	416 ± 42	118 ± 21
H75E crr	80 ± 3	218 ± 19	75 ± 6
H75E H90A crr	67 ± 16	121 ± 32	66 ± 9
H90Q crr	64 ± 12	100 ± 22	62 ± 8
H90E crr	60 ± 8	92 ± 15	61 ± 7

^aCells were grown to mid-log phase at 37°C in Vogel and Bonner medium supplemented with 0.8% Difco nutrient broth, 0.5% glucose, 50 μg of ampicillin per ml, and 40 μg of chloramphenicol per ml. Cells from 50 ml of culture were centrifuged, washed with 25 mM Tris-HCl (pH 8.0), and suspended in 1 ml of Tris buffer. Toluenized cells were assayed for adenylyl cyclase at 30°C as described elsewhere (7). The standard incubation mixture of 0.25 ml contained 25 mM Bicine (pH 8.5), 20 mM MgCl₂, 1 mM dithiothreitol, 1 mM [α-³²P]ATP (20 to 30 cpm/pmol), 1 mM cAMP, 20 mM creatine phosphate, and 50 U of creatine phosphokinase. Dipotassium phosphate (K.Pi) (pH 8.5; 20 mM) and methyl-α-d-glucopyranoside (α-MG; 1 mM) were added as indicated. At 10 and 20 min, 100-μl aliquots were withdrawn and combined with 0.2 ml of 1 N perchloric acid to terminate the reaction. The results are the averages of data from four experiments ± the standard deviations. WT, wild type.