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DNA mechatronic devices switched by K + and by S r 2+ are structurally, topologically, and electronically distinct
Author(s) -
Huang Yu Chuan,
Yu HuaZhong,
Sen Dipankar
Publication year - 2015
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.22595
Subject(s) - chemistry , conformational isomerism , circular dichroism , g quadruplex , dna , duplex (building) , molecular switch , guanine , crystallography , stereochemistry , chromophore , topology (electrical circuits) , nucleotide , molecule , photochemistry , biochemistry , mathematics , organic chemistry , combinatorics , gene
DNAs and RNAs that fold via the formation of guanine quartets form G‐quadruplexes that are often highly diverse in terms of architecture and topology. G‐quadruplexes are specifically stabilized by metal cations such as K + and Sr 2+ , but not Li + . DNA duplexes that incorporate two separated clusters of G•G mismatches (“P‐duplexes”) can function as electronic switches, capable of toggling reversibly from a poorly conductive conformer (E) with only Li + in the solution to a G‐quadruplex incorporating conformer of higher conductivity (C) in the presence of K + . Herein, we report results from fluorescence energy transfer, circular dichroism, charge conduction, and chemical footprinting experiments, which cumulatively demonstrate that P‐duplex E↔C transitions are genuinely mechatronic, with causally coupled mechanical and electronic states. We show, further, that the K + ‐ and the Sr 2+ ‐fuelled E↔C switching of a given P‐duplex are structurally, topologically, and electronically distinct from each other. A single DNA P‐duplex can thus exist in at least three distinguishable mechatronic states in aqueous solution. © 2014 Wiley Periodicals, Inc. Biopolymers 103: 460–468, 2015.