title: Synthesis and triplex forming properties of pyrrolidino pseudoisocytidine containing oligodeoxynucleotides.
abstract: Pyrrolidino pseudo-C-nucleosides are isosteres of natural deoxynucleosides which are protonated at the pyrrolidino ring nitrogen under physiological conditions. As constituents of a triplex forming oligodeoxynucleotide (TFO), the positive charge is expected to stabilise DNA triple helices via electrostatic interactions with the phosphodiester backbone of the target DNA. We describe the synthesis of the pyrrolidino isocytidine pseudonucleoside and the corresponding phosphoramidite building block and its incorporation into TFOs. Such TFOs show substantially increased DNA affinity compared to unmodified oligodeoxynucleotides. The increase in affinity is shown to be due to the positive charge at the pyrrolidino subunit.
authors.affiliation: Department of Chemistry and Biochemistry, University of Berne, Freiestrasse 3, CH-3012, Berne, Switzerland.
authors.forename: Alain
authors.initials: A
authors.lastname: Mayer
authors.forename: Adrian
authors.initials: A
authors.lastname: Häberli
authors.forename: Christian J
authors.initials: CJ
authors.lastname: Leumann
mesh_terms: D001483:Base Sequence; D003562:Cytidine / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides / Q000138:chemical synthesis* / Q000737:chemistry; D011759:Pyrrolidines / Q000737:chemistry*
chemical_list: D009838:Oligodeoxyribonucleotides; D011759:Pyrrolidines; C083576:isocytidine; D003562:Cytidine; C032519:pyrrolidine