Abstract
In this work we carried out a study covering conformational analysis, docking calculations and molecular dynamics (MD) simulations of six excited state intramolecular proton transfer (ESIPT)-fluorescent 2-(2'-hydroxyphenyl)-benzoxazoles, interacting with the Dickerson-Drew (d(CGCGAATTCGCG)2) dodecamer in B-DNA conformation. In the analysis of the molecular docking calculations, the derivatives with the -NH2 group in the phenolic ring presented the most favorable interaction energies with the DNA, and the scores were even more favorable for the ligands containing the -NO2 group as substituent in the benzoxazolic ring. In the analysis of the MD simulations, the complexes showed stable interactions, with minimal induced structural distortions in the DNA, being the largest increase of the Rise parameter when the ligands were intercalated, and also the unwinding of Twist. During all simulations, the ligands showed stable interactions with the oligonucleotide, without denaturation. Considering these interactions and the peculiar photophysical properties of this class of molecules, they could be used as biological probes.
Highlights
Benzazoles belong to a class of molecules with interesting photophysical properties
The ligands with nitro grouping showed more favorable interaction energy than the ligands with methyl grouping, which showed more favorable energies than the ligands with pyridine ring. This affinity is increased with the addition of an amino grouping, as observed in the analysis of molecular docking calculations in both initial and final structures
In the analysis by molecular docking, ligands with the amino group showed more favorable interactions when compared with their respective precursors, with the only exception being the ligands 1a and 2a, both showing the same average energy of interaction
Summary
The heterocyclic derivatives of the 2-(2’-hydroxyphenyl)benzoxazole show an intense fluorescence emission due to the phenomenon of excited state intramolecular proton transfer (ESIPT) with high Stokes shift (difference between the wavelength of maximum absorption and of maximum emission), and high thermal stability They are widely used as synthetic materials to obtain new photoluminescent materials, including precursors: polymer matrices,[1,2] silica,[3,4] cellulosic compounds,[5] fluorescent sensors[6] and chemical sensors.[7].
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