title: Solution structure of a short DNA fragment studied by neutron scattering.
abstract: The solution structure of a DNA fragment of 130 base pairs and known sequence has been investigated by neutron small-angle scattering. In 0.1 M NaCl, the overall structure of the DNA fragment which contains the strong promoter A1 of the Escherichia coli phage T7 agrees with that expected for B-DNA. The neutron scattering curve is well fitted by that of a rigid rod with a length of 44 nm and a diameter of 2 nm. The results were confirmed by quasi-elastic light scattering and analytical centrifugation. The neutron measurements in H2O and D2O buffer reveal a cross-sectional inhomogeneity not detected by X-ray small-angle scattering. This inhomogeneity is caused by the hydration layer around the DNA core and not by the helical structure. The primary solvent shell has a density increased by at least 4-9% compared to bulk water.
mesh_terms: D001482:Base Composition; D002021:Buffers; D004247:DNA / Q000032:analysis*; D009502:Neutrons; D010446:Peptide Fragments / Q000032:analysis*; D012542:Scattering, Radiation; D012996:Solutions; D012997:Solvents; D013329:Structure-Activity Relationship; D013604:T-Phages
chemical_list: D002021:Buffers; D010446:Peptide Fragments; D012996:Solutions; D012997:Solvents; D004247:DNA