Effect of local sugar and base geometry on 13C and 15N magnetic shielding anisotropy in DNA nucleosides.
Density functional theory was employed to study the dependence of 13C and 15N magnetic shielding tensors on the glycosidic torsion angle (chi) and conformation of the sugar ring in 2'-deoxyadenosine, 2'-deoxyguanosine, 2'-deoxycytidine, and 2'-deoxythymidine. In general, the magnetic shielding of the glycosidic nitrogens and the sugar carbons was found to depend on both the conformation of the sugar ring and chi. Our calculations indicate that the magnetic shielding anisotropy of the C6 atom in pyrimidine and the C8 atom in purine bases depends strongly on chi. The remaining base carbons were found to be insensitive to both sugar pucker and chi re-orientation. These results call into question the underlying assumptions of currently established methods for interpreting residual chemical shift anisotropies and 13C and 15N auto- and cross-correlated relaxation rates and highlight possible limitations of DNA applications of these methods.
Faculty of Science, University of South Bohemia and Biology Centre AS CR v.v.i., Branisovská 31, 370 05, Ceské Budejovice, Czech Republic.
Eva
E
Brumovská
Vladimír
V
Sychrovský
Zuzana
Z
Vokácová
Jirí
J
Sponer
Bohdan
B
Schneider
Lukás
L
Trantírek
D016880:Anisotropy; D002236:Carbohydrate Conformation; D004247:DNA / Q000737:chemistry* / Q000378:metabolism; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods; D011684:Purine Nucleosides / Q000737:chemistry* / Q000378:metabolism; D011741:Pyrimidine Nucleosides / Q000737:chemistry* / Q000378:metabolism
D011684:Purine Nucleosides; D011741:Pyrimidine Nucleosides; D004247:DNA