title: Force-induced structural transitions in cross-linked DNA films.
abstract: We report on the preparation and characterization of wet-spun films of sodium DNA in which intermolecular cross-links were introduced following formaldehyde treatment. Raman scattering shows that the DNA in moderately cross-linked films is mainly in the B conformation. Stretching experiments show a transition from plastic to elastomeric behavior with increasing exposure to the cross-linking agent. Elastomeric DNA films are strongly disordered. X-ray diffraction shows that stretching of moderately cross-linked films under controlled high humidity conditions results in increased molecular orientation as well as the appearance of meridional reflections at 7.4-7.8 and 8.2 angstroms. These reflections are not observed for any of the classical conformations associated with mixed sequence DNA, and may arise from extended base-pair stacking in a stretched DNA structure.
authors.affiliation: Universität Konstanz, Fachbereich Physik, 78457, Konstanz, Germany.
authors.forename: A
authors.initials: A
authors.lastname: André
authors.forename: F
authors.initials: F
authors.lastname: Fontaine-Vive
authors.forename: H M
authors.initials: HM
authors.lastname: Möller
authors.forename: T
authors.initials: T
authors.lastname: Fischer
authors.forename: G
authors.initials: G
authors.lastname: Maret
authors.forename: V T
authors.initials: VT
authors.lastname: Forsyth
authors.forename: T
authors.initials: T
authors.lastname: Gisler
mesh_terms: D003432:Cross-Linking Reagents / Q000737:chemistry*; D004247:DNA / Q000737:chemistry* / Q000648:ultrastructure*; D004548:Elasticity; D008567:Membranes, Artificial; D009690:Nucleic Acid Conformation; D044367:Phase Transition; D013314:Stress, Mechanical
chemical_list: D003432:Cross-Linking Reagents; D008567:Membranes, Artificial; D004247:DNA