title: X-ray diffraction from DNA fibres under tension.
abstract: When DNA fibres are stretched during drying, the polymer undergoes a conformational transition. We present quantitative results from X-ray diffraction studies on such fibres held at various ambient relative humidities. These indicate that the molecules are arranged in arrays which are crystalline in projection down the fibre axis. The packing can be explained in terms of a hexagonal cell with a lattice parameter, a, of approximately 13 A which varies with humidity. The patterns contain meridional intensities at 1/3.4 A(-1) and 1/6.5 A(-1), a strong off-meridional intensity at Z=1/5.6 A(-1) and diffuse scatter at Z=1/28 A(-1).
authors.affiliation: Department of Physics, University of York, York, YO10 5DD, UK. rjg@york.ac.uk
authors.forename: R J
authors.initials: RJ
authors.lastname: Greenall
authors.forename: C
authors.initials: C
authors.lastname: Nave
authors.forename: W
authors.initials: W
authors.lastname: Fuller
mesh_terms: D000818:Animals; D001704:Biopolymers / Q000737:chemistry / Q000378:metabolism; D002417:Cattle; D003460:Crystallization; D004247:DNA / Q000737:chemistry* / Q000378:metabolism*; D003890:Desiccation; D006813:Humidity; D009690:Nucleic Acid Conformation; D013950:Thymus Gland; D014867:Water / Q000378:metabolism; D014961:X-Ray Diffraction
chemical_list: D001704:Biopolymers; D014867:Water; D004247:DNA