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.