title: Images of the DNA double helix in water.
abstract: The scanning tunneling microscope can image uncoated DNA submerged in water. The grooves of the double helix were clearly resolved in images of the 146-base pair fragment extracted from calf thymus nucleosome. In contrast to images obtained with dry DNA, the helix pitch varied only a small amount (36 +/- 5 angstroms). The path of the helix shows considerable variation. It is quite straight when the molecules are densely packed, but it curves and bends in isolated molecules.
authors.affiliation: Department of Physics, Arizona State University, Tempe 85287.
authors.forename: S M
authors.initials: SM
authors.lastname: Lindsay
authors.forename: T
authors.initials: T
authors.lastname: Thundat
authors.forename: L
authors.initials: L
authors.lastname: Nagahara
authors.forename: U
authors.initials: U
authors.lastname: Knipping
authors.forename: R L
authors.initials: RL
authors.lastname: Rill
mesh_terms: D000818:Animals; D001482:Base Composition; D002417:Cattle; D004247:DNA / Q000648:ultrastructure*; D008854:Microscopy, Electron; D009690:Nucleic Acid Conformation; D009707:Nucleosomes / Q000032:analysis; D012996:Solutions; D013950:Thymus Gland / Q000648:ultrastructure; D014867:Water
chemical_list: D009707:Nucleosomes; D012996:Solutions; D014867:Water; D004247:DNA