title: Synthesis and biochemical characterization of tricyclothymidine triphosphate (tc-TTP).
abstract: Tricyclo-DNA (tc-DNA) is a conformationally restricted oligonucleotide analogue that exhibits promising properties as a robust antisense agent. Here we report on the synthesis and biochemical characterization of tc-TTP, the triphosphate of a tc-DNA nucleoside containing the base thymine. Tc-TTP turned out to be a substrate for the Vent (exo(-) ) DNA polymerase, a polymerase that allows for multiple incorporations of tc-T nucleotides under primer extension reaction conditions. However, the substrate acceptance is rather low, as also observed for other sugar-modified analogues. Tc-TTP and tc-nucleotide-containing templates do not sustain enzymatic polymerization under physiological conditions; this indicates that tc-DNA-based antisense agents will not enter natural metabolic pathways that lead to long-term toxicity.
authors.affiliation: Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern (Switzerland). hollenstein@dcb.unibe.ch.
authors.forename: Marcel
authors.initials: M
authors.lastname: Hollenstein
authors.forename: Christian J
authors.initials: CJ
authors.lastname: Leumann
mesh_terms: D017931:DNA Primers / Q000737:chemistry; D004259:DNA-Directed DNA Polymerase / Q000737:chemistry; D006575:Heterocyclic Compounds, 3-Ring / Q000737:chemistry*; D009690:Nucleic Acid Conformation; D016376:Oligonucleotides, Antisense / Q000138:chemical synthesis; D013941:Thymine / Q000737:chemistry; D013942:Thymine Nucleotides / Q000737:chemistry*
chemical_list: D017931:DNA Primers; D006575:Heterocyclic Compounds, 3-Ring; D016376:Oligonucleotides, Antisense; D013942:Thymine Nucleotides; D004259:DNA-Directed DNA Polymerase; D013941:Thymine
keywords: nucleoside triphosphates; oligonucleotides; polymerases; primer extension; tricyclo-DNA