title: DNA machines: bipedal walker and stepper.
abstract: The assembly of a "bipedal walker" and of a "bipedal stepper" using DNA constructs is described. These DNA machines are activated by H(+)/OH(-) and Hg(2+)/cysteine triggers. The bipedal walker is activated on a DNA template consisting of four nucleic acid footholds. The forward "walking" of the DNA on the template track is activated by Hg(2+) ions and H(+) ions, respectively, using the thymine-Hg(2+)-thymine complex or the i-motif structure as the DNA translocation driving forces. The backward "walking" is activated by OH(-) ions and cysteine, triggers that destroy the i-motif or thymine-Hg(2+)-thymine complexes. Similarly, the "bipedal stepper" is activated on a circular DNA template consisting of four tethered footholds. With the Hg(2+)/cysteine and H(+)/OH(-) triggers, clockwise or anticlockwise stepping is demonstrated. The operation of the DNA machines is followed optically by the appropriate labeling of the walker-foothold components with the respective fluorophores/quenchers units.
authors.affiliation: Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
authors.forename: Zhen-Gang
authors.initials: ZG
authors.lastname: Wang
authors.forename: Johann
authors.initials: J
authors.lastname: Elbaz
authors.forename: Itamar
authors.initials: I
authors.lastname: Willner
mesh_terms: D001483:Base Sequence; D003545:Cysteine / Q000737:chemistry*; D004247:DNA / Q000737:chemistry*; D005453:Fluorescence; D006863:Hydrogen-Ion Concentration; D008628:Mercury / Q000737:chemistry*; D008969:Molecular Sequence Data; D049329:Nanostructures / Q000737:chemistry*; D009690:Nucleic Acid Conformation
chemical_list: D004247:DNA; D008628:Mercury; D003545:Cysteine