TABLE 2.

Kinetics of pore formation by Cry1Aa interhelical loop mutants in M. sexta midgut brush border membrane vesicles

Toxin	Mutation site	Mean delaya,b ± SEM (min)		Mean swelling rateb,c ± SEM (% vol recovery/min)
		pH 7.5	pH 10.5	pH 7.5	pH 10.5
Cry1Aa	None	0.48 ± 0.06	0.65 ± 0.02	30 ± 7	21 ± 1
F50C	α1-α2	1.03 ± 0.07**	1.3 ± 0.1**	8.7 ± 0.8*	6.2 ± 0.3**
I88C	α2-α3	0.33 ± 0.02	0.35 ± 0.03**	37 ± 2	32 ± 2**
P121C	α3-α4	0.40 ± 0.04	0.65 ± 0.08	26.4 ± 0.5	17.6 ± 0.5*
T122C	α3-α4	0.41 ± 0.02	0.55 ± 0.07	25.2 ± 0.5	20.6 ± 0.6
N123C	α3-α4	0.56 ± 0.03	1.3 ± 0.1**	19 ± 1	4.8 ± 0.4**
Q151C	α4-α5	0.9 ± 0.4	3.4 ± 0.4**	5.1 ± 0.5*	2.2 ± 0.3**
Y153C	α4-α5	1.18 ± 0.09**	1.8 ± 0.7	6.8 ± 0.5*	5.6 ± 0.2**
W182C	α5-α6	1.8 ± 0.3*	4 ± 2	5 ± 1*	2.4 ± 0.8**
W219C	α6-α7	0.8 ± 0.2	1.1 ± 0.2	15 ± 3	7 ± 2**
S252C	α7-β1a	1.1 ± 0.2*	2.2 ± 0.5*	8 ± 1*	4.7 ± 0.6**

^aTime required for volume recovery to reach 5%.

^bA significant difference from the corresponding value for Cry1Aa is indicated by an asterisk (*, P < 0.05; **, P < 0.01).

^cMaximum slope of the Boltzmann sigmoidal curves fitted to the data points.