title: Effect of spatial inhomogeneity in dielectric permittivity on DNA double layer formation.
abstract: In solutions of tetramethylammonium (TMA+) DNA (double stranded) without added low-molecular-weight salt, the counterion radial density is calculated using the cylindrical Poisson-Boltzmann equation with a distance-dependent quasimacroscopic dielectric permittivity. Comparisons with small-angle neutron scattering data indicate that any inhomogeneity in dielectric permittivity is confined to one or two solvent layers from the DNA surface. At least for TMA+, which may be too large to penetrate the grooves of DNA to any significant extent, dielectric inhomogeneity modeled in this way has no detectable effect on the radial distribution.
authors.affiliation: Department of Biochemistry, University of Minnesota, St. Paul, Minnesota 55108, USA. j.maarel@rulgca.leidenuniv.nl
authors.forename: J R
authors.initials: JR
authors.lastname: van der Maarel
mesh_terms: D055592:Biophysical Phenomena; D001703:Biophysics; D004247:DNA / Q000737:chemistry*; D007477:Ions; D008956:Models, Chemical; D009502:Neutrons; D000644:Quaternary Ammonium Compounds; D012542:Scattering, Radiation; D012996:Solutions; D055672:Static Electricity
chemical_list: D007477:Ions; D000644:Quaternary Ammonium Compounds; D012996:Solutions; D004247:DNA; C027917:tetramethylammonium