Different modes of interaction between hydrated magnesium ion and DNA functional groups: database analysis and ab...

Area of Science:

• Biochemistry
• Structural Biology
• Computational Chemistry

Background:

• Magnesium ions are essential for DNA structure and function.
• The precise mechanisms of DNA-magnesium interactions remain incompletely understood.
• Existing knowledge lacks comprehensive details on the various interaction modes.

Purpose of the Study:

• To elucidate the specific modes of interaction between magnesium ions and DNA.
• To provide experimental and computational evidence for these interaction mechanisms.
• To quantify the energetic contributions of different interaction pathways.

Main Methods:

• Analysis of existing DNA crystal structures complexed with magnesium ions.
• Ab initio quantum chemical calculations, including restricted Hartree-Fock and Density Functional Theory.
• Restrained and unrestrained geometry optimizations to study reaction coordinates and energy landscapes.

Main Results:

• Identified two primary modes of magnesium-DNA interaction: direct coordination and water-mediated hydrogen bonding.
• Computational analysis revealed energy minima and barriers (5-15 kcal/mol) consistent with experimental observations.
• Both interaction modes occur with similar probabilities, with water-mediated interactions being frequently preferred.

Conclusions:

• The study clarifies the dual interaction modes of magnesium ions with DNA.
• Water-mediated interactions, often overlooked, play a significant role and are frequently preferred.
• Findings enhance the understanding of magnesium's fundamental role in DNA stability and function.