Fig. 5.

An intersubunit clash when binding ssDNA is removed when a horseshoe h2i conformation is converted to a helical conformation. a The CMG:DNA model (PDB 5U8S⁴¹ has a horseshoe conformation in the h2i of Mcm3, Mcm5, and Mcm2 that severely clashes with the ps1β of the neighboring subunit. b This clash is removed when the horseshoe portion is modified to helix. Mcm3 is in orange, Mcm5 in red, and Mcm2 in purple. The ps1β and h2i are emphasized in bold color with the rest of the protein in light color. The model in panel b was generated from our MCM:ssDNA structure by Chainsaw⁶⁶ followed by brief geometry minimization with phenix.geometry_minimization⁵⁹. The map of CMG:DNA (EMD_8518 (ref. ⁴¹)) is drawn in the vicinity of the DNA for both panels