Recombinant Schizosaccharomyces pombe DNA replication ATP-dependent helicase dna2 (dna2), partial

Key enzyme involved in DNA replication and DNA repair. Involved in Okazaki fragments processing by cleaving long flaps that escape fen1: flaps that are longer than 27 nucleotides are coated by replication protein A complex (RPA), leading to recruit dna2 which cleaves the flap until it is too short to bind RPA and becomes a substrate for fen1. Is a target of the intra-S phase checkpoint, associating with stalled replication forks when phosphorylated at Ser-219 and preventing the stalled replication forks from reversing. Also involved in 5'-end resection of DNA during double-strand break (DSB) repair by mediating the cleavage of 5'-ssDNA. Also required for the production of G-rich single-strand overhangs at telomere ends and thus in telomere length maintenance. Possesses different enzymatic activities, such as single-stranded DNA (ssDNA)-dependent ATPase, 5'-3' helicase and endonuclease activities. While the ATPase and endonuclease activities are well-defined and play a key role in Okazaki fragments processing and DSB repair, the 5'-3' DNA helicase activity is atypical: it cannot load onto its tracking strand internally and has an absolute free 5'-end requirement. Helicase activity may promote the motion of dna2 on the flap, helping the nuclease function.