Selective parallel G-quadruplex recognition by a NIR-to-NIR two-photon squaraine

Abstract

A selective and efficient nonlinear squaraine fluorescent probe for parallel G-quadruplexes suitable for NIR-to-NIR two-photon imaging procedures is reported.

A site-specific self-assembled light-up rotor probe for selective recognition and stabilization of c-MYC G-quadruplex DNA

“…Indeed, supramolecular sensors operating via DIE are successful in selectively detecting parallel G4 topologies, however neither of these G4-binders have been sequence/site-specific. [13][14][15][16] This sensing mechanism strongly differs from the aggregation-caused quenching (ACQ) previously reported for G4-or duplex minor-groove binders based on cyanine dyes. 17,18 In this study, we envisioned that a two-step switching mechanism based on (1) recognition-driven disassembly (i.e.…”

“…[1][2][3]12 Supramolecular fluorescence sensors with distinguishable and controllable readout responses were recently designed as topology-specific G4-binders. [13][14][15][16] Their G4-interactive binding model relies on the disassembly of the molecular aggregate (disaggregation-induced emission, DIE) in the presence of highly accessible π-surfaces such as those found in parallel G4 topologies. Parallel G4 structures are devoid of either adjacent lateral or diagonal loops, and can therefore provide better π-stacking platforms for the accommodation of the aromatic core of these ligands.…”

A Light‐up Logic Platform for Selective Recognition of Parallel G‐Quadruplex Structures via Disaggregation‐Induced Emission

“…Next, by performing electronic circular dichroism (ECD) spectroscopy, we assessed the morphological changes occurring on the c‐MYC sG4 structure in the presence of CQ4 (Supporting Information, Figures S44 and S45). The ECD spectra showed that the overall secondary structure of c‐MYC sG4 was fully conserved even upon the addition of an excess of 4 equiv of ligand . Therefore, in spite of the high K a value determined, CQ4 does not induce any topological changes or destabilization effect on the G4 scaffold, a highly important feature in the design of ideal in vivo G4 fluorescent probes.…”

Identification of optimal fluorescent probes for G-quadruplex nucleic acids through systematic exploration of mono- and distyryl dye libraries

“…To summarize, a systematic analysis enabled us to select the optimal probes within the styryl dye family (i.e., those displaying high quantum yield and brightness, excellent light-up factor, and remarkable selectivity for a certain G4 class). A comparison with literature data demonstrates that dyes 1p and 1u largely outperform, in terms of brightness and quadruplex-vs-duplex selectivity, the widely used fluorescent probes, such as thioflavin T (ThT, Φ = 0.25, in the presence of 22AG /K + conditions) and thiazole orange (TO, Φ = 0.19 in the presence of 22AG /K + conditions) [92], and approach the brightest G4-DNA probes developed so far, such as trialryimidazole IZCM-7 (Φ = 0.52, in the presence of c-myc ) [52] and the NIR-emitting squaraine dye CAS-C1 (Φ of up to 0.74 with parallel G4-DNA) [93]. Applications of these dyes can be multiple.…”