Figure 4.

SPR-based assay for ATP-stimulated disassembly of PT. PT holotoxin was captured on a SPR slide coated with GD1a. After establishing a baseline measurement (0 RIU) corresponding to the mass of the sensor-bound holotoxin, ATP and 0.5% CHAPS were added to the perfusion buffer at 200 s (asterisk). Anti-PTS1 and anti-PTS4 antibodies (Ab) were then added sequentially, as indicated by the arrowheads. (A) Native PT was exposed to 10 μM ATP. (B) PTDM was exposed to 100 μM ATP. One of two representative experiments is shown for each condition.