TABLE 2.

Kinetics of pore formation by Cry1Aa α4 mutants in M. sexta midgut brush border membrane vesicles

Toxin	Delaya (min)		Swelling rateb (% vol recovery/min)
	pH 7.5	pH 10.5	pH 7.5	pH 10.5
Cry1Aa	0.45 ± 0.03	0.57 ± 0.04	26.7 ± 3.3	23.5 ± 1.8
R127E	0.64 ± 0.02**c	1.33 ± 0.13**	15.4 ± 0.3	6.6 ± 0.7**
R127N	0.38 ± 0.03	0.58 ± 0.02	30.1 ± 1.9	19.3 ± 0.9
E128C	3.06 ± 0.40**	4.01 ± 0.22**	2.7 ± 0.3**	2.0 ± 0.2**
R131D	1.35 ± 0.15**	NAd	6.2 ± 0.5**	NA
R131E	1.42 ± 0.20**	NA	6.2 ± 0.8**	NA
R131H	1.61 ± 0.24**	>6.00	6.7 ± 0.6**	0.4 ± 0.3**
R131Q	2.24 ± 0.32**	NA	3.5 ± 0.6**	NA
D136C	2.89 ± 0.56**	1.84 ± 0.22**	4.1 ± 0.4**	5.4 ± 0.9**
D136N	2.03 ± 0.26**	3.17 ± 0.42**	4.5 ± 0.1**	3.0 ± 0.8**

^aTime required for volume recovery to reach 5%.

^bSlope at the inflection point of the Boltzmann sigmoidal curves fitted to the data points.

^c**, Significantly different from the corresponding value obtained for Cry1Aa (P < 0.01).

^dNA, not active at pH 10.5.