title: An approach to the structure determination of nucleic acid analogues hybridized to RNA. NMR studies of a duplex between 2'-OMe RNA and an oligonucleotide containing a single amide backbone modification.
abstract: The backbone modification amide-3, in which -CH2-NH-CO-CH2- replaces -C5'H2-O5'-PO2-O3'-, is studied in the duplex d(G1-C2-G3-T4.T5-G6-C7-G8)*mr(C9-G10-C11-A12-A13-C14-G15+ ++-C16) where . indicates the backbone modification and mr indicates the 2'-OMe RNA strand. The majority of the exchangeable and non-exchangeable resonances have been assigned. The assignment procedure differs from standard methods. The methyl substituent of the 2'-OMe position of the RNA strand can be used as a tool in the interpretation. The duplex structure is a right-handed double helix. The sugar conformations of the 2'-OMe RNA strand are predominantly N-type and the 2'-OMe is positioned at the surface of the minor groove. In the complementary strand, only the sugar of residue T4 is found exclusively in N-type conformation. The incorporation of the amide modification does not effect very strongly the duplex structure. All bases are involved in Watson-Crick base pairs.
authors.affiliation: Ciba-Geigy AG, Basel, Switzerland.
authors.forename: M J
authors.initials: MJ
authors.lastname: Blommers
authors.forename: U
authors.initials: U
authors.lastname: Pieles
authors.forename: A
authors.initials: A
authors.lastname: De Mesmaeker
mesh_terms: D001482:Base Composition; D001483:Base Sequence; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009690:Nucleic Acid Conformation; D009693:Nucleic Acid Hybridization; D009838:Oligodeoxyribonucleotides / Q000737:chemistry*; D012313:RNA / Q000737:chemistry* / Q000378:metabolism; D013696:Temperature
chemical_list: D009838:Oligodeoxyribonucleotides; D012313:RNA