Fig. 3.

The pH-dependent conversion of (PA₆₃)₇ prepore to pore. (a) Formation of an SDS-resistant state correlates with the formation of pore in solution (24). In the absence of CMG2, this conversion takes place between pH 7 and 7.5. In the presence of CMG2 (and ATR/TEM8, not shown), a pH between 6 and 6.5 is required. The slower pore migration in the presence of CMG2 may indicate that CMG2 remains bound, although the differences between the multiple pore bands are not yet understood. (b) Excimer formation by pyrene-labeled N306C (PA₆₃)₇ occurs at a pH between 7.0 and 8.3 (Upper) but requires a pH between 4.9 and 6.2 in the presence of the CMG2 VWA domain (Lower).