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. 1999 Feb;67(2):496–503. doi: 10.1128/iai.67.2.496-503.1999

FIG. 5.

FIG. 5

FIG. 5

FIG. 5

Effects of CNF1 treatment on GTPase activities and nucleotide binding of Cdc42 and Rac1. (A and B) Wild-type (WT) Cdc42, wild-type Rac1, and the respective Q61E mutants were incubated without (WT and Q61E) and with (WT) ΔCNF1 (molar ratio of GTPase to toxin, 5:1) for 3 h, and thereafter the GTPases were loaded with [γ-32P]GTP. Data are given as means and standard deviations (n = 3). (A) Loaded GTPases were incubated without (intrinsic) and with p50GAP (molar ratio of p50GAP to Cdc42/Rac, 1:50) for 4 min at 37°C. The samples were then filtered through nitrocellulose, and the radioactivity remaining on the filters was counted. (B) GTPase activity was determined with Cdc42 at different p50GAP/Cdc42 ratios. (C) Wild-type Cdc42, Q61E Cdc42, and CNF1-treated Cdc42 (0.5 μM each) were incubated with 2 μM mant-GDP, and the increase in fluorescence at 444 nm (due to the higher intensity of bound mant-GDP excited at 357 nm) was recorded. The k values are the dissociation rates for GDP.