A study of the interaction tyrosine and DNA using voltammetry and spectroscopy methods

Area of Science:

• Electrochemistry
• Biophysical Chemistry
• Spectroscopy

Background:

• Tyrosine (Tyr) is a crucial amino acid involved in various biological processes.
• Understanding the interaction between small molecules like Tyr and DNA is vital for drug development and molecular biology.
• Carbon nanotube-modified electrodes offer enhanced sensitivity for studying biomolecular interactions.

Purpose of the Study:

• To investigate the interaction mechanism between tyrosine and double-stranded DNA.
• To quantify the binding affinity and parameters of Tyr-DNA interaction.
• To explore the utility of modified electrodes in studying such interactions.

Main Methods:

• Cyclic voltammetry was employed using bare and DNA-modified glassy carbon electrodes (GCE).
• Single-walled carbon nanotubes (SWCNT/GCE) and multi-walled carbon nanotubes (MWCNT/GCE) were used to modify the electrodes.
• Fluorescence emission spectroscopy and UV-vis spectroscopy were utilized to analyze the interaction.

Main Results:

• Electrochemical studies indicated an intercalative interaction between Tyr and DNA, evidenced by decreased current and a positive shift in the Tyr oxidation peak.
• Calculated parameters include transfer coefficient (α), heterogeneous rate constant (k(s)), and surface concentration (Γ).
• Binding constants for Tyr-DNA interaction were determined using the Hill model (3.98×10^3 L/mol) and Stern-Volmer plot (3.37×10^3 L/mol), with 2 binding sites identified.

Conclusions:

• Tyrosine intercalates into double-stranded DNA, as confirmed by multiple spectroscopic and electrochemical techniques.
• The use of DNA/SWCNT/GCE and DNA/MWCNT/GCE platforms provides sensitive methods for studying Tyr-DNA interactions.
• The quantitative binding data offers insights into the molecular recognition mechanisms between amino acids and nucleic acids.