Relationships between super(31)P Chemical Shift Tensors and Conformation of Nucleic Acid Backbone: A DFT Study

Density functional theory (DFT) has been applied to study the conformational dependence of super(31)P chemical shift tensors in B-DNA. The gg and gt conformations of backbone phosphate groups representing B sub(I)- and B sub(II)-DNA have been examined. Calculations have been carried out on static mo...

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Published in:The journal of physical chemistry. B 2007-01, Vol.111 (1), p.2658-2667
Main Authors: Precechtelova, Jana, Munzarova, Marketa L, Novak, Petr, Sklenar, Vladimir
Format: Article
Language:English
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Summary:Density functional theory (DFT) has been applied to study the conformational dependence of super(31)P chemical shift tensors in B-DNA. The gg and gt conformations of backbone phosphate groups representing B sub(I)- and B sub(II)-DNA have been examined. Calculations have been carried out on static models of dimethyl phosphate (dmp) and dinucleoside-3',5'-monophosphate with bases replaced by hydrogen atoms in vacuo as well as in an explicit solvent. Trends in super(31)P chemical shift anisotropy (CSA) tensors with respect to the backbone torsion angles alpha, zeta, beta2, and epsilon are presented. Although these trends do not change qualitatively upon solvation, quantitative changes result in the reduction of the chemical shift anisotropy. For alpha and zeta in the range from 270 degree to 330 degree and from 240 degree to 300 degree , respectively, the delta sub(22) and delta sub(33) principal components vary within as much as 30 ppm, showing a marked dependence on backbone conformation. The calculated super(31)P chemical shift tensor principal axes deviate from the axes of O-P-O bond angles by at most 5 degree . For solvent models, our results are in a good agreement with experimental estimates of relative gg and gt isotropic chemical shifts. Solvation also brings the theoretical delta sub(iso) of the gg conformation closer to the experimental gg data of barium diethyl phosphate.
ISSN:1520-6106
1520-5207
DOI:10.1021/jp0668652PII:S1520-6106(06)06865-9