B-DNA model systems in non-terran bio-solvents: implications for structure, stability and replication

Area of Science:

• Astrobiology
• Computational Chemistry
• Molecular Biology

Background:

• The molecular recognition of DNA base pairs is crucial for genetic information transfer.
• Understanding DNA stability and replication in diverse chemical environments is key to assessing the possibility of extraterrestrial life.

Purpose of the Study:

• To computationally investigate the behavior of DNA base pairs in various solvents, including potential extraterrestrial environments.
• To determine how solvent polarity affects DNA base pairing and replication fidelity.

Main Methods:

• Dispersion-corrected density functional theory (DFT) calculations.
• Implicit solvation models were used to simulate gas phase and solvent environments (toluene, chloroform, ammonia, methanol, water).
• Analysis of Watson-Crick and mismatched B-DNA base pairs.

Main Results:

• Solvent polarity significantly influences the hydrogen-bonding affinities and selectivities of DNA base pairs.
• Ammonia, a less polar solvent than water, demonstrated stronger hydrogen-bonding affinities.
• However, ammonia showed reduced selectivity for correct Watson-Crick base pair incorporation compared to water.

Conclusions:

• The study proves the viability of DNA replication in non-terran environments like ammonia.
• The findings contribute to understanding the conditions necessary for life's existence on exoplanetary bodies.
• Medium-dependent molecular recognition is a critical factor for genetic code machinery.