title: Light scattering study of natural DNAs over a wide range of molecular weights: Evidence for compaction of the large molecules.
abstract: This work reports light scattering measurements on DNA in aqueous solutions (100mM NaCl, 1mM EDTA and 10mM Tris-HCl buffer, pH 7.8) over a wide range of molecular weights (10(2)-10(5) base pairs) and shows that, in the above standard solvent, shorter chains (<10(4) base pairs) behave as a "wormlike chain" and their diffusion coefficients as obtained by dynamic light scattering measurements, confirm the prediction of standard wormlike model, whilst longer chains (>10(4) base pairs) behave in a different manner. Dynamic and static light scattering and SEM analysis indicate that DNA molecules 10(5) base pairs long, condense into compact structures in our solvent conditions. Calculations done using a wormlike model are also presented and discussed in comparison both to our experimental data and to other data reported in the literature.
authors.affiliation: Dipartimento di Fisica e Astronomia, Università di Catania. 6, Viale A. Doria, I-95125 Catania, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Zimbone
authors.forename: Pietro
authors.initials: P
authors.lastname: Baeri
authors.forename: Maria Luisa
authors.initials: ML
authors.lastname: Barcellona
authors.forename: Giovanni
authors.initials: G
authors.lastname: Li Volti
authors.forename: Gabriele
authors.initials: G
authors.lastname: Bonaventura
authors.forename: Orazio
authors.initials: O
authors.lastname: Viscuso
mesh_terms: D000818:Animals; D004247:DNA / Q000737:chemistry*; D004269:DNA, Bacterial / Q000737:chemistry / Q000648:ultrastructure; D004058:Diffusion; D006801:Humans; D008027:Light; D016982:Micrococcus luteus / Q000737:chemistry; D008970:Molecular Weight; D012542:Scattering, Radiation
chemical_list: D004269:DNA, Bacterial; D004247:DNA