Measurement of single-molecule reactions can elucidate microscopic mechanisms that are often hidden from ensemble analysis. This presentation report the acid-base titration of a single DNA duplex confined within the wild-type ?-hemolysin (?-HL) nanopore for up to 3 hours. Analysis of the pH-dependent kinetics of >100,000 base flipping events of a single GC base pair using a hidden Markov kinetic model demonstrates that protonation/deprotonation occurs while the base pair is in the intra-helical state. Our experiments correspond to the longest single-molecule chemical reaction kinetic measurements performed using a nanopore.
















Henry White (University of Utah)