Table 4.

Additive or non-additive effects of positions ‘59’ and ‘89’ on autodephosphorylation rate

Response Regulator	Substitutions	Expected Valuea	Actual Valueb	Absolute Value of Difference
CheY	59D-89L	0.15	-0.64	0.79
	59E-89H	-0.40	-0.70	0.30
	59M-89R	-0.29	-1.42	1.13
	59M-89K	-0.05	-1.51	1.46
	59K-89Y	-0.90	-1.61	0.71
Spo0F	‘59’E-‘89’L	2.37	2.03	0.34
	‘59’N-‘89’E	2.28	2.03	0.25
	‘59’N-‘89’H	1.49	1.64	0.15
	‘59’N-‘89’L	1.96	1.93	0.03

^aExpected value for no interaction = log₁₀(‘59’ single substitution rate constant/wildtype rate constant) + log₁₀(‘89’ single substitution rate constant/wildtype rate constant). Rate constants from Tables 2 and 3.

^bActual value = log₁₀(double substitution rate constant/wildtype rate constant)