Photoswitchable DNA-binding properties of a photochromic spirooxazine derivative

Abstract

An N-methylphenanthrolinium-annelated spirooxazine derivative 2(SO) whose DNA-intercalating properties are reversibly changed by a photochromic reaction was prepared. Upon irradiation at 350 nm the spirooxazine is transformed to the corresponding photomerocyanine 2(PM) that binds to DNA. After irradiation with visible light the spirooxazine 2(SO), which exhibits no significant DNA-binding properties, is regained. The association of 2(PM) with DNA was examined by CD and absorption spectroscopy, fluorescent intercalator displacement and viscometric titration.

Naphthalene Imide Conjugates: Formation of Supramolecular Assemblies, and the Encapsulation and Release of Dyes through DNA‐Mediated Disassembly

“…Changesi nt he dynamic viscosity of DNA werem onitored with increasing conjugatec oncentration.W eo bserved av alue of 1.1 AE 0.02 mPa sf or ct-DNA (0.3 mm)i nb uffer at 25 8C, which gradually increased to 1.57 AE 0.01 and 1.43 AE 0.01 mPa s in the presence of conjugate 1 (0.1 mm)o r2 (0.1 mm), respectively,u nder identicalc onditions.T he viscosity changes observed indicate that these systemsu ndergo an intercalative binding mode, similart or eported examples. [17] Further,t he meltingt emperature of synthetic polynucleotide poly(dA·dT)poly(dA·dT) (T m = 44 8C) substantially increased to 66 or 54 8Ci n the presence of conjugates 1 and 2,r espectively ( Figure 6), which indicatedt hat both 1 and 2 significantly stabilise the duplex, predominantly through intercalative interactions. [18]…”

Copper(II)‐Controlled Molecular Glue for Mismatched DNA

“…Reversible control of DNA hybridization by external stimuli is essential for the realization of DNA‐based machines, DNA switches, dynamic and self‐assembled DNA materials and nanostructures, and drug delivery . Thus, small‐molecule ligands whose DNA‐binding properties can be modulated through photochemical reactions, redox reactions, prototropic equilibrium, metal ion coordination, or a combination of these, can be employed as “switchable” ligands to control the stability of double‐stranded DNA and, in selected cases, induce hybridization or denaturation of DNA strands . However, in the cited examples, the binding of ligands to double‐stranded DNA is not sequence‐specific.…”

Photochromic Materials in Biochemistry

“…The photochromic species could be incorporated into the strand backbone in place of a nucleobase or ribose moiety or also by appending a photoswitch to an existing base pair. Photocontrol can also be achieved with external photochromic agents, for example, a ligand with light-dependent affinity or intercalation ability [95][96][97][98].…”