FIG. 3.

TNS analysis of pH-induced hydrophobic transitions in toxin B. Twenty picomoles of toxin B was incubated with 150 μM TNS for 20 min at 37°C. Samples were analyzed for changes in TNS fluorescence. The fluorescent spectrum of each pH is shown and labeled; each spectrum represents the experimental sample with background (TNS and buffer alone) subtracted. TNS fluorescence for samples above pH 5.0 were not above background levels. Similar relative fluorescence was obtained in two consecutive repetitions of this experiment.