title: Parallel stranded DNA under the scanning tunnelling microscope.
abstract: Using scanning tunnelling microscopy, we have directly observed parallel stranded DNA helixes of 43 nucleotides in length. The double helix is right-handed and has an average spacing, 17.43 A (+/- 1 S.D.: 2.30 A), and an average apparent depth, 4.79 A (+/- 1 S.D.: 1.04 A) for each groove. The average pitch of the helical turn is 34 A (+/- 1 S.D.: 3.35 A) and consists of no more than ten base pairs. The diameter of the helix is approx. 17-20 A. Our results provide direct evidence for the existence of a parallel structure of DNA in vitro and some details of its fine structure.
authors.affiliation: Shanghai Institute of Cell Biology, Shanghai Open Laboratory of Life Sciences, China.
authors.forename: J D
authors.initials: JD
authors.lastname: Zhu
authors.forename: M Q
authors.initials: MQ
authors.lastname: Li
authors.forename: L Z
authors.initials: LZ
authors.lastname: Xiu
authors.forename: J Q
authors.initials: JQ
authors.lastname: Zhu
authors.forename: J
authors.initials: J
authors.lastname: Hu
authors.forename: M M
authors.initials: MM
authors.lastname: Gu
authors.forename: Y L
authors.initials: YL
authors.lastname: Xu
authors.forename: L P
authors.initials: LP
authors.lastname: Zhang
authors.forename: Z Q
authors.initials: ZQ
authors.lastname: Huang
authors.forename: B K
authors.initials: BK
authors.lastname: Chernov
mesh_terms: D001483:Base Sequence; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004247:DNA / Q000737:chemistry / Q000648:ultrastructure*; D016252:Microscopy, Scanning Tunneling; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation
chemical_list: D004247:DNA