Investigation of tetrabromobisphenol A interacting with DNA nitrogen bases using experimental and density functional theory methods.

The interactions of tetrabromobisphenol A (TBBPA) with the DNA nitrogen bases – guanine, adenine, thymine, and cytosine – were investigated, using ultraviolet–visible spectroscopy, cyclic voltammetry, anodic differential pulse voltammetry, and density functional theory simulation. Bonding constants of the TBBPA–DNA nitrogen base complexes were calculated. Global chemical reactivity descriptors including chemical potential, electronegativity, and electrophilicity indices were adopted to evaluate the chemical reactivity of TBBPA and DNA nitrogen bases. The condensed Fukui function was calculated to reveal reactive sites. The interaction energies between TBBPA and the nitrogen bases were also calculated. TBBPA interacted as an electrophile with guanine, adenine, and cytosine; with thymine, it served as a nucleophile. The interactions of TBBPA with the nitrogen bases followed the order: guanine > adenine > thymine > cytosine. The TBBPA–guanine complex exhibited the highest charge transfer, the largest bonding constant, and the most negative interaction energy. [ABSTRACT FROM AUTHOR]