Figure 3.

pH dependences of FCS-measured formation of membrane competent form of diphtheria toxin T-domain (symbols and lines) and ANX (16) (only fitting curves are shown for ANX). Titration profiles of the T-domain are shifted toward neutral pH and are less dependent on the lipid composition of the vesicles: 25PC:75PG, 75PC:25PG and 90PC:25PG are shown in blue, red and green respectively. The data were fitted to Eq. 6 to determine the apparent pKa and n values presented on the graph. Experimental details are the same as in (16).