B-{DNA} Structure and Stability: The Role of Nucleotide Composition and Order
- Autori: Celine Nieuwland; Trevor A. Hamlin; C{'{e}}lia Fonseca Guerra; Giampaolo Barone; F. Matthias Bickelhaupt
- Anno di pubblicazione: 2022
- Tipologia: Articolo in rivista
- OA Link: http://hdl.handle.net/10447/537197
Abstract
We have quantum chemically analyzed the influence of nucleotide composition and sequence (that is, order) on the stability of double-stranded B-DNA triplets in aqueous solution. To this end, we have investigated the structure and bonding of all 32 possible DNA duplexes with Watson-Crick base pairing, using dispersion-corrected DFT at the BLYP-D3(BJ)/TZ2P level and COSMO for simulating aqueous solvation. We find enhanced stabilities for duplexes possessing a higher GC base pair content. Our activation strain analyses unexpectedly identify the loss of stacking interactions within individual strands as a destabilizing factor in the duplex formation, in addition to the better-known effects of partial desolvation. Furthermore, we show that the sequence-dependent differences in the interaction energy for duplexes of the same overall base pair composition result from the so-called "diagonal interactions" or "cross terms". Whether cross terms are stabilizing or destabilizing depends on the nature of the electrostatic interaction between polar functional groups in the pertinent nucleobases.