title: The influence of phosphorothioate on charge migration in single and double stranded DNA: a theoretical approach.
abstract: In this study the influence of the phosphorothioate internucleotide bond on the electronic properties of single and double-stranded short nucleotides has been investigated at the M06-2X/6-31+G** level of theory in the gaseous phase. Due to the chirality of the phosphorus atom in a phosphorothioate (PT) internucleotide diester bond, the adiabatic/vertical mode of electron affinity/ionization potential, spin density and molecular orbital distribution, as well as structural analysis were taken under consideration for the single stranded (ss) R(P) and S(P) diastereomers of d[G(PS)G] and for double stranded (ds) d[G(PS)G]*d[C(PO)C], in comparison with the corresponding parent phosphate compounds. Moreover, the excitation states, HOMO and LUMO energies were calculated using a TD-DFT methodology at the M06-2X/6-31+G**//M06-2X/6-31++G** level of theory in the aqueous phase. The obtained results show that the PT plays a significant role in the case of ss-oligonucleotides, and to a much smaller extent in ds-oligomers.
authors.affiliation: Food Science Department, Medical University of Lodz, ul. Muszynskiego 1, 90-151 Lodz, Poland. Bolek.Karwowski@wp.pl.
authors.forename: Boleslaw T
authors.initials: BT
authors.lastname: Karwowski
mesh_terms: D020029:Base Pairing; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D009711:Nucleotides / Q000737:chemistry; D010710:Phosphates / Q000737:chemistry*; D011789:Quantum Theory
chemical_list: D009711:Nucleotides; D010710:Phosphates; C083120:phosphorodithioic acid; D004247:DNA