title: Charge, Diffusion, and Current Fluctuations of Single-Stranded DNA Trapped in an MspA Nanopore.
abstract: We report effective charges and diffusion constants of several different single-stranded DNA oligonucleotides trapped in an MspA nanopore. Nucleotide identity is found to have a substantial influence on effective charges and diffusion constants. These quantities are determined from escape time experiments for a DNA molecule attached to a NeutrAvidin molecule that, unlike the DNA, does not pass through the pore. Correlations are reported between oligonucleotide effective charges and current blockages, and between their diffusion constants and DNA-induced current blockage fluctuations. We also report an unanticipated source of current fluctuations that reflects a discrete blockage current level structure. We posit that this is associated with interactions between the NeutrAvidin molecule and the MspA nanopore.
authors.affiliation: Department of Physics, Harvard University, Cambridge, Massachusetts.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Fleming
authors.affiliation: Department of Physics, Harvard University, Cambridge, Massachusetts.
authors.forename: Bo
authors.initials: B
authors.lastname: Lu
authors.affiliation: Department of Physics, Harvard University, Cambridge, Massachusetts; School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts. Electronic address: golovchenko@physics.harvard.edu.
authors.forename: Jene A
authors.initials: JA
authors.lastname: Golovchenko
mesh_terms: D004277:DNA, Single-Stranded / Q000737:chemistry* / Q000378:metabolism*; D004058:Diffusion; D004553:Electric Conductivity; D058608:Nanopores; D018272:Porins / Q000737:chemistry*
chemical_list: D004277:DNA, Single-Stranded; D018272:Porins; C121838:mspA protein, Mycobacterium smegmatis