title: How flexible are DNA constituents? The quantum-mechanical study.
abstract: Relaxed force constants (RFCs) and vibrational root-mean-square deviations have been evaluated by the original calculation method for conformational parameters of the DNA structural units and their constituents: nucleic acid bases (uracile, thymine, cytosine, adenine and guanine) and their 'building blocks' (benzene, pyrimidine, imidazole and purine molecules), as well as the DNA backbone structural units: tetrahydrofuran, 1,2-dideoxyribose, methanol and orthophosphoric acid. It has been found that the RFCs for nomenclature torsions beta, gamma, epsilon; and sugar pseudorotation angle P in 1,2-dideoxyribose are sensible to the molecule conformation and their values are in the range of 1-25 kcal/(mole·rad²) obeying the inequality K(γ)> K(ε) > K(ρ) > K(β). The RFCs values for endocyclic torsions of nucleic acid bases six-member rings lie within 15-45 kcal/(mole·rad²) in pyrimidines and within 20-60 kcal/(mole·rad²) in purines. It is shown that the quantum zero-point motion effectively neglects the amino group non-planarity in cytosine, adenine and partially in guanine.
authors: Taras Shevchenko National University of Kyiv, Faculty of Physics, 4 Hlushkova Prosp., Kyiv 03022, Ukraine. tim_mail@ukr.net
authors: T Yu
authors: TY
authors: Nikolaienko
authors: L A
authors: LA
authors: Bulavin
authors: D M
authors: DM
authors: Hovorun
mesh_terms: D004247:DNA / Q000737:chemistry*; D009690:Nucleic Acid Conformation; D011687:Purines / Q000737:chemistry; D011743:Pyrimidines / Q000737:chemistry; D011789:Quantum Theory
chemical_list: D011687:Purines; D011743:Pyrimidines; D004247:DNA; C030986:pyrimidine; C030985:purine