The elucidation of major groove binding of Dinitro-ortho-cresol herbicide to DNA: a multi-approach of voltammetric, spectroscopic, and computational modeling methods

Abstract

This study examined the binding of Dinitro-ortho-cresol (DNOC) herbicide with Calf thymus deoxyribonucleic acid (Ct-DNA) using spectroscopic, voltammetric, docking, and molecular dynamics methods. Cyclic voltammetry results showed two irreversible cathodic peaks (peaks I and II) at the potentials of −0.48 and −0.76 V, which are related to the reduction of -NO₂ groups of DNOC to -NHOH groups. The cyclic voltammetry results measured the binding constant and binding site size of DNOC to DNA at 3.58 × 10³ and 0.85, respectively. Also, the diffusion constants for DNOC (D_f) and DNOC-DNA complex (D_b) were 3.4 × 10⁻³ and 6.5 × 10⁻⁵, respectively. A great decrease in the intensity of vibrations related to guanine and cytosine functional groups was observed compared to adenine and thymine. These changes show that DNOC has a greater tendency to interact with guanine and cytosine rather than adenine and thymine. All voltammetric and fluorescence spectroscopy data shows that the interaction between the DNOC and DNA is more thorough in the major groove. These experimental data are in agreement with theoretical data.