Stabilization and Multiple-Responsive Recognition of Natural Base Pairs in Water by a Cationic Cage

Abstract

The hydrogen-bonded (H-bonded) base pairs, double H-bonded A•T and triple H-bonded G•C in DNA, are important units for storing, encoding, and expressing genetic information. Owing to the interference from water, however, the formation of H-bonded base pairs from short deoxynucleotide fragments such as mono-or di-deoxynucleotide are not easily achieved in aqueous solutions. Here, we report a host-guest strategy to stabilize H-bonded base pairs of monodeoxynucleotides by a tetraphenylethene (TPE)-based octacationic cage to form host-guest complexes in water. The X-ray structure of cage ⊃ base pair complex clearly shows the double hydrogen bonds between A and T can be stabilized inside the hydrophobic cavity of the cage to form a H-bonded base pair (A•T) with the Hoogsteen pairing rule. Furthermore, the adaptive chirality of the cage with excess right-handed (P) rotational conformation of TPE units is triggered by two base pairs (A•T and G•C) to exhibit differentiated multiple responses, including turn-on/turn-off fluorescence, negative circular dichroism, and negative circularly polarized luminescence in water.

A fluorescent, chirality-responsive, and water-soluble cage as a multifunctional molecular container for drug delivery

“…Recently, we reported that a tetraphenylene-based octacationic cage (1) can recognize biomolecules such as deoxynucleotides, nucleotides, and DNA to exhibit multiple responsive behaviors with fluorescence, circular dichroism (CD), and circularly polarized luminescence (CPL) signals. [34][35][36][37] In theory, 1 with a hydrophobic cavity and water solubility could be used as a molecular container for drug delivery in aqueous solution. [38][39][40] On the one hand, 1 has several advantages in aqueous recognition and detection.…”

A tetraphenylethene-based hexacationic molecular cage with an open cavity

“…Particularly, a TPE-based octacationic cage with four pillars, which has a closed cavity (Scheme 1a, left), has been constructed for host–guest recognition, fluorescent sensors, energy and electron transfer, and drug delivery. 18 Here, we report a TPE-based hexacationic molecular cage ( 1 ) with only three pillars, which has an open cavity (Scheme 1a, right). Compared with the four-pillared cage, 1 with an open cavity exhibits 1 : 2 or 1 : 1 host–guest recognition for large nicotinamide adenine dinucleotide (NAD) molecules including NADH and NAD + with dual responses of circular dichroism (CD) and fluorescence in water.…”

“…9–13 Given their good fluorescence and novel structure, TPEs have been successfully introduced into the supramolecular and material fields for the construction of macrocyclic compounds, 8 metal–organic frameworks (MOFs) and covalent-organic frameworks (COFs). 14,15 In previous reports, our group has developed a series of TPE-based monocyclophanes, 16 dicyclophanes, 17 3D cages, 18 and supramolecular organic frameworks (SOFs) 19 for molecular recognition and luminescence materials. Particularly, a TPE-based octacationic cage with four pillars, which has a closed cavity (Scheme 1a, left), has been constructed for host–guest recognition, fluorescent sensors, energy and electron transfer, and drug delivery.…”

Enantioselective assembly and recognition of heterochiral porous organic cages deduced from binary chiral components

“…Chirality is vital to biological processes and widely exists in various biological structures at the molecular level, including polysaccharides, proteins and DNA. 10 Incorporation of chirality into artificial functional materials provides new objectives towards chiral separation, 11 stereospecific catalysis, 12 chiral recognition, 13 and unique chiroptical properties. 14 Self-assembly depending on chiral recognition and discrimination has been used to prepare chiral functional supramolecular materials through noncovalent interactions such as electrostatic interactions, 15 π–π interactions, 16 hydrogen bonding, 17 and metal-coordination bonds.…”