title: NMR study of the effect of sugar-phosphate backbone ethylation on the stability and conformation of DNA double helix.
abstract: Temperature variation studies of the imido proton NMR and 31P NMR resonances of the self-associated d(C-C-A-A-G-A-T-T-G-G) and d[C-C-A-A-G-p(Et)-A-T-T-G-G] duplexes (both the R and S diastereoisomers) and the heteroduplexes formed with their complementary strand d(C-C-A-A-T-C-T-T-G-G) were carried out in aqueous solution. Results demonstrate that phosphate backbone ethylation did not disrupt the interstrand hydrogen bonding involved in double-helix formation but perturbed the helix. The S isomer perturbed the duplex more than the R isomer. The line broadening patterns and faster fraying motion in the alkylated duplexes compared to those in the nonalkylated duplexes indicate that the perturbation introduced in the middle propagates along the backbone to the end of the duplex.
mesh_terms: D050260:Carbohydrate Metabolism; D004247:DNA / Q000187:drug effects* / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D009838:Oligodeoxyribonucleotides / Q000378:metabolism; D010710:Phosphates / Q000378:metabolism*; D011487:Protein Conformation; D013696:Temperature
chemical_list: D009838:Oligodeoxyribonucleotides; D010710:Phosphates; D004247:DNA