DNA Primer Extension with Cyclopropenylated 7-Deaza-2'-deoxyadenosine and Efficient Bioorthogonal Labeling in Vitro and in Living Cells

A deoxyadenosine triphosphate (dATP) analogue for DNA labeling was synthesized with the 1-methylcyclopropene (1MCP) group at the 7-position of 7-deaza-2'-deoxyadenosine and applied for primer extension experiments. The real-time kinetic data reveals that this 1MCP-modified dATP analogue is incorporated into DNA much faster than that of the similarly 1MCP-modified deoxyuridine triphosphate (dUTP) analogue. The postsynthetic fluorescent labeling of these oligonucleotides works efficiently according to PAGE analysis, and can be applied for immobilization of a functional antibody on a surface. Site-specific labeling at two different positions in DNA was achieved and the bioorthogonality of the postsynthetic fluorescent labeling was demonstrated in living HeLa cells.