title: Scanning tunneling microscopy of nucleic acids.
abstract: The scanning tunneling microscope (STM) has been used to measure properties of poly(rA).poly(rU) and DNA, such as helical pitch, half-period oscillations that were interpreted as the alternation between the major and minor grooves, and interhelical spacing. Average pitches were measured by two-dimensional Fourier transforms and by topographic profiles along the fiber axes. Values were typically 7 percent less than standard dimensions of A-form RNA and B-form DNA fibers. This result is compatible with the mild dehydration that occurred under air-drying conditions. More extensive dehydration typically led to 19 percent shrinkage. Analysis of specific regions allowed local variations in helical pitch as small as 1 angstrom to be detected, thus demonstrating that the STM can visualize functionally significant modulations of nucleic acid structure.
authors: Department of Chemical Engineering and Materials Science Interfacial, University of Minnesota, Minneapolis 55455.
authors: G
authors: G
authors: Lee
authors: P G
authors: PG
authors: Arscott
authors: V A
authors: VA
authors: Bloomfield
authors: D F
authors: DF
authors: Evans
mesh_terms: D004247:DNA / Q000648:ultrastructure*; D005583:Fourier Analysis; D008854:Microscopy, Electron; D009690:Nucleic Acid Conformation; D011063:Poly A-U; D012313:RNA / Q000648:ultrastructure*
chemical_list: D011063:Poly A-U; D012313:RNA; D004247:DNA