Changes of WT-CFTR gating kinetics upon ATP/PATP exchange. (A) A continuous single-channel current trace (a representative trace from 10 single-channel recordings) showing the effects of ligand exchanges between ATP (black traces) and PATP (red traces). (B) A history plot of the recording shown in A. Kinetic parameters were extracted with a 15-s time window. The hypothesized nucleotide binding status of CFTR at different time windows is marked.