title: Selectively 13C-enriched DNA: 13C and 1H assignments of a triple helix by two-dimensional relayed HMQC experiments.
abstract: We present NMR studies of an intramolecular triple helix, the three strands of which have been linked by a hexaethylene glycol chain. To overcome the generally encountered difficulties of assignment in the homo-pyrimidine strands, the carbon Cl' of the pyrimidines were selectively 13C-enriched. Assignments of the aromatic and sugar protons were obtained from NOESY-HMQC and TOCSY-HMQC spectra. We show that the recognition of a DNA duplex by a third strand via triplex formation is easily carried out in solution by observing the changes of the 1Hl'-13Cl' connectivities as a function of pH. Furthermore, the conformation of the sugars has been found to be C2'-endo, on the basis of the coupling constant values directly measured in an HSQC spectrum.
authors.affiliation: Centre de Biophysique Moléculaire, CNRS, Orléans, France.
authors.forename: O
authors.initials: O
authors.lastname: Bornet
authors.forename: G
authors.initials: G
authors.lastname: Lancelot
authors.forename: L
authors.initials: L
authors.lastname: Chanteloup
authors.forename: T T
authors.initials: TT
authors.lastname: Nguyen
authors.forename: J M
authors.initials: JM
authors.lastname: Beau
mesh_terms: D001483:Base Sequence; D002247:Carbon Isotopes; D003432:Cross-Linking Reagents; D004247:DNA / Q000737:chemistry*; D005026:Ethylene Glycols; D006859:Hydrogen; D007553:Isotope Labeling; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation
chemical_list: D002247:Carbon Isotopes; D003432:Cross-Linking Reagents; D005026:Ethylene Glycols; C077067:hexaethylene glycol; D006859:Hydrogen; D004247:DNA