Do weak interactions affect the biological behavior of DNA? A DFT study of CpG island-like chains

Simulating the Helicase Enzymatic Action on ds-DNA: A First-Principles Molecular Dynamics Study

Understanding DNA replication is fundamental for advancements in fields such as genetics, molecular biology, and medical research. In this study, we investigate the mechanical characteristics of three distinct double-stranded DNA molecules (ds-DNA) as each of them is unwound into two individual single strands. To simulate the helicase action, the double strands are subjected to Langevin forces. By use of sequential and helical steering harmonic forces that simulate the enzymatic action of a helicase, each strand of ds-DNA is opened. The research focuses on determining thermal fluctuations, energy changes, charge variations, and individual forces associated with the separation of each base pair in the examined sequences. The findings emphasize the importance of combining quantum mechanical techniques with an implicit force model. This integrative approach is versatile and provides valuable insights into the essential processes governing DNA mechanisms, particularly in relation to cellular functioning, thereby enhancing our understanding of biological molecules.

Formations of bimolecular barbituric acid complexes through hydrogen bonding interactions: DFT analyses of structural and electronic features

Formations of bimolecular barbituric acid (BA) complexes through hydrogen-bonding (HB) interactions were investigated in this work. BA has been known as a starting compound of pharmaceutical compounds developments, in which the molecular and atomic features of parent BA in homo-paring with another BA molecule were investigated here. The models were optimized to reach the stabilized structures and their properties were evaluated at the molecular and atomic scales. Density functional theory (DFT) calculations were performed to provide required information for achieving the goal of this work. Six dimer models were obtained finally according to examining all possible starting dimers configurations for involving in optimization calculations. N-H . . . O and C-H . . . O interactions were also involved in dimers formations besides participation of the X-center of parent BA in interaction. Molecular and atomic scales features were evaluated for characterizing the dimers formations. As a consequence, several configurations of BA dimers were obtained showing the importance of performing such structural analyses for developing further compounds from BA.