title: Oligonucleotide N3'-->P5' phosphoramidates.
abstract: Synthetic oligonucleotides and their analogs have attracted considerable interest recently. These compounds may lead to highly specific therapeutic agents, as well as to powerful diagnostic tools. Here, we present the synthesis of uniformly modified oligodeoxyribonucleotide N3'-->P5' phosphoramidates containing 3'-NHP(O)(O-)O-5' internucleoside linkages and the study of their hybridization properties. Thermal dissociation experiments show that these compounds form very stable duplexes with single-stranded DNA, RNA, and with themselves following Watson-Crick base pairing. The duplex thermal stability was enhanced by 2.2-2.6 degrees C per modified linkage compared with phosphodiesters. The structure of complexes formed by phosphoramidates closely resembles that of RNA oligomers and corresponds to an A form, as judged by CD spectroscopy. N3'-->P5' phosphoramidates also form stable triplexes with double-stranded DNA under near-physiological conditions when natural phosphodiesters fail to do so. Physicochemical characteristics of the amidates are similar to those of RNA oligomers, even though they are composed of 2'-deoxyfuranose-based nucleosides.
authors.affiliation: Lynx Therapeutics, Inc., Hayward, CA 94545, USA.
authors.forename: S M
authors.initials: SM
authors.lastname: Gryaznov
authors.forename: D H
authors.initials: DH
authors.lastname: Lloyd
authors.forename: J K
authors.initials: JK
authors.lastname: Chen
authors.forename: R G
authors.initials: RG
authors.lastname: Schultz
authors.forename: L A
authors.initials: LA
authors.lastname: DeDionisio
authors.forename: L
authors.initials: L
authors.lastname: Ratmeyer
authors.forename: W D
authors.initials: WD
authors.lastname: Wilson
mesh_terms: D000577:Amides; D001483:Base Sequence; D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry*; D004355:Drug Stability; D007202:Indicators and Reagents; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009690:Nucleic Acid Conformation; D009838:Oligodeoxyribonucleotides / Q000138:chemical synthesis / Q000737:chemistry; D009841:Oligonucleotides / Q000138:chemical synthesis / Q000737:chemistry*; D009843:Oligoribonucleotides / Q000138:chemical synthesis / Q000737:chemistry; D010756:Phosphoric Acids; D012313:RNA / Q000737:chemistry*
chemical_list: D000577:Amides; D007202:Indicators and Reagents; D009838:Oligodeoxyribonucleotides; D009841:Oligonucleotides; D009843:Oligoribonucleotides; D010756:Phosphoric Acids; D012313:RNA; D004247:DNA; C011067:phosphoramidic acid