Docking on the DNA G-quadruplex: a molecular electrostatic potential study.

Area of Science:

• Biochemistry
• Computational Chemistry
• Drug Discovery

Background:

• G-quadruplexes are guanine-rich, four-stranded nucleic acid structures involved in key biological processes, including telomere regulation.
• Telomeric G-quadruplex DNA is emerging as a promising target for new anticancer therapies.

Purpose of the Study:

• To investigate the molecular electrostatic potential (MEP) and frontier molecular orbitals (HOMO/LUMO) of G-quadruplex structures.
• To compare these properties with DNA duplexes and assess their implications for drug docking and anticancer drug design.

Main Methods:

• Density Functional Theory (DFT) calculations at the B88LYP/6-31G* level, including dispersion corrections.
• Analysis of MEP and electron density distributions of G-quadruplex and DNA duplex models.
• Computational docking studies of daunomycin anticancer drugs with the G-quadruplex.

Main Results:

• G-quadruplex MEP and frontier orbital electron densities exhibit distinct topological deformations compared to DNA duplexes due to their coiled conformation.
• The most electronegative electrostatic active zone of the G-quadruplex is located at its upper region.
• Electrostatic interactions facilitate favorable binding (stacking) between the G-quadruplex and daunomycin anticancer drugs.

Conclusions:

• The unique electrostatic landscape of G-quadruplexes influences their interactions with small molecules.
• Computational insights into G-quadruplex MEP and orbitals can guide the rational design of novel anticancer drugs targeting these structures.
• G-quadruplexes present a viable target for developing new chemotherapeutic agents.