Light scattering study of natural DNAs over a wide range of molecular weights: Evidence for compaction of the large molecules.
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.
Zimbone
Massimo
M
Dipartimento di Fisica e Astronomia, Università di Catania. 6, Viale A. Doria, I-95125 Catania, Italy.
Baeri
Pietro
P
Barcellona
Maria Luisa
ML
Li Volti
Giovanni
G
Bonaventura
Gabriele
G
Viscuso
Orazio
O
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
D004269:DNA, Bacterial; D004247:DNA