FIG. 2.

SpoIIAA induces the release of σ^G from SpoIIAB:σ^G complexes. Fluorescence spectroscopy was used to measure changes in the fluorescence intensity of the single tryptophan in σ^G. The results of three independent experiments are shown in panels A to C. Purified σ^G (0.8 μM) and SpoIIAB (1.25 μM) were mixed, and at time zero, ATP (100 μM) was added to the solution and the fluorescence intensity of the sample was determined. Different concentrations of SpoIIAA (5 μM [A], 10 μM [B], and 15 μM [C]) were added to the samples 10 min later.