title: Circular dichroism studies of 6-N-methylated adenylyladenosine and adenylyluridine and their parent compounds. Thermodynamics of stacking.
abstract: The temperature dependence of the circular dichroism spectra of two adenylyladenosine and three adenylyluridine dinucleotides in aqueous solution have been studied. The effect of methylation of the N-6 position of the adenylyl moieties on the thermodynamic parameters of the stacking equilibrium was investigated applying a two-state model for the thermodynamic analysis of the experimental data. It is shown that the methylated compounds allow a more accurate analysis of the data and that methylation stabilizes the stacking interaction by a relative decrease of the entropy of unstacking.
mesh_terms: D000249:Adenosine Monophosphate / Q000031:analogs & derivatives*; D001482:Base Composition; D002942:Circular Dichroism; D015226:Dinucleoside Phosphates; D008745:Methylation; D009690:Nucleic Acid Conformation; D013816:Thermodynamics
chemical_list: D015226:Dinucleoside Phosphates; C026692:N(6),N(6)-dimethyladenylyl(3'-5')N(6),N(6)-dimethyladenosine; C006412:adenylyl-(3'-5')-adenosine; C006413:adenylyl-(3'-5')-uridine; D000249:Adenosine Monophosphate