In eukaryotes, DNA replication depends on loading the ring-shaped helicase, Mcm2–7 onto double-stranded DNA and subsequent activation by GINS–Cdc45. Using single-particle EM reconstructions, the Mcm2–7 forms ring hexamers that are open between Mcm2 and Mcm5. When present, GINS and Cdc45 both seal off this gap. In the presence of a non-hydrolyzable ATP analog, two pores are formed. In this way, the complex could promote duplex opening and then segregate the two strands by partitioning them into the two pores.
- Alessandro Costa
- Ivar Ilves
- James M Berger
