H-bond interactions between arsenite and deoxynucleotides at different pH values: A combined computational and...

Area of Science:

• Computational Chemistry and Molecular Spectroscopy
• Environmental Science and Sensor Development

Background:

• Deoxynucleotides are potential monomers for arsenite ion-imprinted polymers due to aptamer recognition capabilities.
• The precise binding mechanism between arsenite and deoxynucleotides remains unclear, hindering sensor development.

Purpose of the Study:

• To investigate the binding interactions between arsenite and deoxynucleotides (dAMP, dTMP, dGMP, dCMP) across a wide pH range (1-14).
• To elucidate the role of pH and hydrogen bonding in arsenite-deoxynucleotide complex formation.
• To identify optimal conditions for arsenite detection using deoxynucleotide-based materials.

Main Methods:

• Density Functional Theory (DFT) calculations to model binding affinities and complex stability.
• Spectroscopy analysis, including UV/VIS, FT-IR, and NMR, to experimentally validate computational findings.
• Reduced Density Gradient (RDG) analysis to characterize hydrogen bonding interactions.

Main Results:

• Deoxyguanosine monophosphate (dGMP) exhibited the highest calculated affinity for arsenite.
• Stable complexes were identified involving arsenite binding to the phosphate group of dGMP and the nucleobase of dAMP, dCMP, and dTMP.
• Optimal pH ranges for binding were determined for each deoxynucleotide, aligning with UV/VIS experimental data.
• Hydrogen bonds were identified as the primary interaction, with their strength modulated by pH.

Conclusions:

• The study provides a detailed understanding of arsenite-deoxynucleotide interactions, highlighting dGMP's strong affinity.
• Hydrogen bonding plays a critical role, and its strength is pH-dependent, offering insights for sensor design.
• The findings support the use of deoxynucleotides in arsenite ion-imprinted polymers and sensor development.