title: Poly(d2NH2A-dT): two-dimensional NMR shows a B to A conversion in high salt.
abstract: Poly(d2NH2A-dT) forms a structure in high salt that is clearly distinct from the B form present in low salt. Two-dimensional nuclear Overhauser effect (2D NOE) NMR spectra establish that the conformation of the high-salt form is not Z. Correlations of observed cross peaks in the 2D NOE spectra and estimated interproton distances of the common DNA conformations are consistent only with an A form or closely related structure. This interpretation is also consistent with the negative circular dichroic band observed in the high-salt form of poly(d2NH2A-dT) and in A-form ribohomopolymer helices containing 2NH2A.
mesh_terms: D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D009994:Osmolar Concentration; D011089:Polydeoxyribonucleotides
chemical_list: D011089:Polydeoxyribonucleotides; C048037:poly(thymidylyl-(5'-3')-2-amino-2-deoxy-5'-adenylic acid)