title: pH-stimulated concurrent mechanical activation of two DNA "tweezers". A "SET-RESET" logic gate system.
abstract: A DNA tweezer consisting of C-rich arms is kept in the "closed" form by hybridization of the arms with a nucleic acid cross-linker. At acidic pH (pH = 5.2), the arms are stabilized through the formation of the i-motif, C-quadruplex structures, releasing the cross-linking nucleic acid and transforming the tweezer to its "opened" state. At neutral pH (pH = 7.2), the C-quadruplex structures are dissociated, resulting in the capturing of the cross-linking nucleic acid and the closure of the tweezer. By the reversible treatment of the tweezer at pH = 5.2 and at pH = 7.2, the tweezer system is cycled between the open and closed states, respectively, followed by a FRET process between a fluorophore-quencher pair that labels the tweezer. Also the concurrent activation of two DNA tweezers by pH stimuli is described. The pH-induced opening of one tweezer (tweezer A) by the formation of C-quadruplex (pH = 5.2) and the release of the cross-linking nucleic acid result in the closure of a second tweezer (tweezer B) by the hybridization of the released strand with the arms of tweezer B. The dissociation of the C-quadruplex structures (pH = 7.2) results in the favored translocation of the cross-linking nucleic acid from tweezer B to A. By the cycling of the pH of the system between pH = 5.2 and pH = 7.2, the concurrent opening and closure of the two tweezers are accomplished. The two tweezers system performs a SET-RESET logic gate operation, where the pH stimuli act as inputs.
authors.affiliation: The Institute of Chemistry, The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
authors.forename: Johann
authors.initials: J
authors.lastname: Elbaz
authors.forename: Zhen-Gang
authors.initials: ZG
authors.lastname: Wang
authors.forename: Ron
authors.initials: R
authors.lastname: Orbach
authors.forename: Itamar
authors.initials: I
authors.lastname: Willner
mesh_terms: D039301:Computers, Molecular; D004247:DNA / Q000737:chemistry* / Q000648:ultrastructure*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006863:Hydrogen-Ion Concentration; D036103:Nanotechnology / Q000295:instrumentation*; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D013314:Stress, Mechanical
chemical_list: D004247:DNA