title: alpha-DNA-V. Parallel annealing, handedness and conformation of the duplex of the unnatural alpha-hexadeoxyribonucleotide alpha-[d(CpApTpGpCpG)] with its beta-complement beta-[d(GpTpApCpGpC)] deduced from high field 1H-NMR.
abstract: The beta-complementary hexamer, beta-d[GTACGC], to the alpha-sequence, alpha-d[CATGCG], was synthesized by the phosphotriester method. The non-exchangeable proton assignments were obtained using 1D- and 2D-NMR techniques, including NOE, COSY and NOESY. The beta-strand exists as a random coil at 21 degrees C; however, at 4 degrees C, it forms an antiparallel self-recognition duplex annealing at positions 1-4. The beta-strand was annealed to the alpha-strand, and confirmation of complete annealing was obtained by detection and assignment of the six base pair imino protons in H2O/D2O solution at 21 degrees C. 1D-NOE experiments of the alpha, beta duplex d[alpha-(CATGCG) X beta-(GTACGC)] reveal that (i) it exists in aqueous solution in a conformation that belongs to the B family, (ii) it is 70 +/- 10% right-handed, (iii) the sugar-base orientations of the beta-strand are anti, and the deoxyribose units exist predominantly in the 2'-endo-3'-exo conformation. NOE measurements of the imino proton signals in the alpha, beta duplex reveal that the duplex exhibits parallel polarity.
authors: Université des Sciences et Techniques du Languedoc, UA 488 du CNRS, Montpellier, France.
authors: F
authors: F
authors: Morvan
authors: B
authors: B
authors: Rayner
authors: J L
authors: JL
authors: Imbach
authors: M
authors: M
authors: Lee
authors: J A
authors: JA
authors: Hartley
authors: D K
authors: DK
authors: Chang
authors: J W
authors: JW
authors: Lown
mesh_terms: D001482:Base Composition; D001483:Base Sequence; D004247:DNA; D006859:Hydrogen; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D009690:Nucleic Acid Conformation; D009838:Oligodeoxyribonucleotides; D013816:Thermodynamics
chemical_list: D009838:Oligodeoxyribonucleotides; D006859:Hydrogen; D004247:DNA