Switchable and dynamic G-quadruplexes and their applications

Abstract

G-Quadruplexes represent important functional constituents in biology, chemistry, nanotechnology, and material science. The article reviews the dynamic reconfiguration of G-quadruplexes and their applications in diverse scientific disciplines.

Modulating the Lifetime of DNA Motifs Using Visible Light and Small Molecules

“…At pH <5, cytosine residues are protonated, leading to the formation of i-motif 4 , which consequently triggers the formation of G-quadruplex 5 in the presence of potassium ions (Figure a). The i-motif and G-quadruplex structures are naturally occurring and have been used in a wealth of DNA-based nanotechnologies: as biochemical sensors in vivo , mechanochemical devices, and to design new therapeutics . Controlling the temporality of these structures may lead to next-generation devices and soft robotics materials capable of work and motion, based on genomic sequences.…”

Recent Advances in DNA Nanostructures Applied in Sensing Interfaces and Cellular Imaging

“…Besides the traditional Watson–Crick base pairing-based nucleic acids, various features of the base constituents provide diverse alternative principles to influence the structure and function of nucleic acids. − These principle mechanisms include switchable reconfiguration G-rich strands into the G-quadruplex unit, with the assistance of K + and their separation by crown-ether; ,, stabilization/destabilization of photoisomerizer-intercalated DNA duplex, for example the trans- / cis- azobenzene molecule units; − and the hydrogen bond-stabilized DNA triplex structures . In all these structures, the G-quadruplex attracts significant attention as the functional nanounit in chemistry, biology, and nanotechnology, especially in the biosensing research field. − As shown in Figure A, Li and co-workers monitored the electrochemical behavior of a single G-quadruplex nanostructure intercalated with hemin, G-quadruplex/hemin DNAzyme, to mimick HRP catalytic function on a gold surface . In the presence of targeted miRNA, the G-quadruplex nanostructure was formed on the gold surface, oxidizing hydroquinone (HQ) present in the sample solution to benzoquinone (BQ) by H 2 O 2 that is catalyzed by G-quadruplex/hemin DNAzyme.…”

Dynamic Reconfigurable DNA Nanostructures, Networks and Materials

“…[1] In addition to the base-pair stabilization of duplex nucleic acid structures and dictated dynamic strand displacement of duplex nucleic acids by appropriate fuel-/ anti-fuel strands, [2] the structural information embedded in the biopolymer includes the sequence-guided reconfiguration of single strands into secondary structures in the presence of auxiliary triggers. Examples include the pHinduced reconfiguration of cytosine-rich strands into i-motif structures (pH < 5.5) and their separation at neutral pH values, [3] the K + -ion (or Sr 2 + , Pb 2 + ) stimulated stabilization of guanosine-rich strands into G-quadruplex assemblies and their separation in the presence of crown ethers (CE), [1,4] the auxiliary strand-induced formation of T-A • T or C-G • C + triplex structures and their pH-stimulated separation or auxiliary-strand displacement, [5] the metal-ion (Ag + or Hg 2 + ) stabilization of C-mismatched or T-mismatched duplexes by C-Ag + -C or T-Hg 2 + -T bridges and their dissociation in the presence of ligands, e.g., cysteine, [6] and the stabilization and destabilization of duplex nucleic acids by photoisomerizable intercalators, such as trans/cis-azobenzene units. [7] In addition, duplex nucleic acid structures provide instructive information towards enzyme-driven transformations on the nucleic acid scaffolds.…”