. "Flap endonuclease-1 (FEN-1), a structure specific nuclease, is an essential enzyme for eukaryotic DNA replication and repair. The crystal structure of FEN-1 from Methanococcus jannaschii, determined at 2.0 A resolution, reveals an active site with two metal ions residing on top of a deep cleft where several conserved acidic residues are clustered. Near the active site, a long flexible loop comprised of many basic and aromatic residues forms a hole large enough to accommodate the DNA substrate. Deletion mutations in this loop significantly decreased the nuclease activity and specificity of FEN-1, suggesting that the loop is critical for recognition and cleavage of the junction between single and double-stranded regions of flap DNA." . . . "Nat. Struct. Biol." . "Baek K." . "Hwang K.Y." . "Cho Y." . "Kim H.-Y." . "1998"^^ . "707-713" . "The crystal structure of flap endonuclease-1 from Methanococcus jannaschii." . "5" . "doi:10.1038/1406" .