It has been shown that individual molecules of single stranded DNA can be driven electrophoretically through a single Staphylococcus aureus ?-hemolysin ion channel. Polynucleotides thread through the channel as extended chains and the polymer-induced ionic current blockades exhibit stable modes during the interactions. Additionally, we show here that polynucleotides can be used to probe structural features of the ?-hemolysin channel itself. Specifically, both pore length and channel aperture profile can be estimated. The results are consistent with the channel crystal structure and suggest that polymer-based ?molecular rulers? may prove useful in deducing the structures of nanometer- scale pores in general.
Citation: Journal of Chemical Physics
Pub Type: Journals
alpha hemolysin, alpha toxin, DNA, ion channel, nanopore, polymer confinement, polynucleotide, structure-function