title: The role of molecular structure of sugar-phosphate backbone and nucleic acid bases in the formation of single-stranded and double-stranded DNA structures.
abstract: Our previous DFT computations of deoxydinucleoside monophosphate complexes with Na(+)-ions (dDMPs) have demonstrated that the main characteristics of Watson-Crick (WC) right-handed duplex families are predefined in the local energy minima of dDMPs. In this work, we study the mechanisms of contribution of chemically monotonous sugar-phosphate backbone and the bases into the double helix irregularity. Geometry optimization of sugar-phosphate backbone produces energy minima matching the WC DNA conformations. Studying the conformational variability of dDMPs in response to sequence permutation, we found that simple replacement of bases in the previously fully optimized dDMPs, e.g. by constructing Pyr-Pur from Pur-Pyr, and Pur-Pyr from Pyr-Pur sequences, while retaining the backbone geometry, automatically produces the mutual base position characteristic of the target sequence. Based on that, we infer that the directionality and the preferable regions of the sugar-phosphate torsions, combined with the difference of purines from pyrimidines in ring shape, determines the sequence dependence of the structure of WC DNA. No such sequence dependence exists in dDMPs corresponding to other DNA conformations (e.g., Z-family and Hoogsteen duplexes). Unlike other duplexes, WC helix is unique by its ability to match the local energy minima of the free single strand to the preferable conformations of the duplex.
authors.affiliation: Autonomous University of Puebla, Puebla, 72570, Mexico.
authors.forename: Valeri
authors.initials: V
authors.lastname: Poltev
authors.forename: Victor M
authors.initials: VM
authors.lastname: Anisimov
authors.forename: Victor I
authors.initials: VI
authors.lastname: Danilov
authors.forename: Dolores
authors.initials: D
authors.lastname: Garcia
authors.forename: Carolina
authors.initials: C
authors.lastname: Sanchez
authors.forename: Alexandra
authors.initials: A
authors.lastname: Deriabina
authors.forename: Eduardo
authors.initials: E
authors.lastname: Gonzalez
authors.forename: Francisco
authors.initials: F
authors.lastname: Rivas
authors.forename: Nina
authors.initials: N
authors.lastname: Polteva
mesh_terms: D002241:Carbohydrates / Q000737:chemistry*; D004247:DNA / Q000737:chemistry*; D004277:DNA, Single-Stranded / Q000737:chemistry*; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D009696:Nucleic Acids / Q000737:chemistry*; D010710:Phosphates / Q000737:chemistry*; D011687:Purines / Q000737:chemistry*; D011743:Pyrimidines / Q000737:chemistry*; D015203:Reproducibility of Results; D013816:Thermodynamics
chemical_list: D002241:Carbohydrates; D004277:DNA, Single-Stranded; D009696:Nucleic Acids; D010710:Phosphates; D011687:Purines; D011743:Pyrimidines; D004247:DNA; C030985:purine
keywords: DFT computations; DNA conformation families; DNA sequence dependence; deoxydinucleoside monophospates; single-strand interactions