title: Post-synthetic modification of DNA by inverse-electron-demand Diels-Alder reaction.
abstract: There is currently a tremendous interest in developing bioorthogonal "click chemistry" methods for the modification of biopolymers. Very recently, inverse-electron-demand Diels-Alder reactions have received attention, but to date they have not been applied to nucleic acids. Here we describe the first example of DNA modification by inverse-electron-demand Diels-Alder reaction. We synthesized four different building blocks for 3'-terminal, 5'-terminal, and internal incorporation of norbornene dienophiles into oligonucleotides. These DNA strands were either directly reacted with suitably derivatized tetrazine dienes or first subjected to enzymatic manipulations. We demonstrate that the inverse-electron-demand Diels-Alder reaction allows efficient site-specific post-synthetic conjugation, often at a 1:1 stoichiometry, without any side reaction. The reaction works in aqueous media at room temperature, and no transition metals are required. Both short chemically synthesized oligonucleotides and long enzymatically amplified DNA strands were successfully conjugated.
authors.affiliation: Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Im Neuenheimer Feld 364, Heidelberg 69120, Germany.
authors.forename: Juliane
authors.initials: J
authors.lastname: Schoch
authors.forename: Manfred
authors.initials: M
authors.lastname: Wiessler
authors.forename: Andres
authors.initials: A
authors.lastname: Jäschke
mesh_terms: D001483:Base Sequence; D004247:DNA / Q000138:chemical synthesis* / Q000737:chemistry* / Q000235:genetics; D018736:DNA Adducts / Q000138:chemical synthesis* / Q000737:chemistry*; D004583:Electrons; D009838:Oligodeoxyribonucleotides / Q000138:chemical synthesis / Q000737:chemistry / Q000235:genetics; D013777:Tetrazoles / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D018736:DNA Adducts; D009838:Oligodeoxyribonucleotides; D013777:Tetrazoles; D014867:Water; D004247:DNA