Interaction of flap endonuclease-1 and replication protein A with photoreactive intermediates of DNA repair.

A new method for enzymatic synthesis of radioactive DNA flapped structures containing a photoreactive dCMP moiety at a branch point with 4-(4-azido-2,3,5,6-tetrafluorobenzylidene-hydrazinocarbonyl)butylcarbamoyl group attached at exo-N-position of cytosine was developed. The formation of complexes of flap endonuclease-1 (FEN-1) with flapped DNA was shown by photoaffinity modification and gel retardation assays. The substrate properties of the flapped structures with different flap lengths were studied in the reaction of endonuclease cleavage catalyzed by FEN-1.