Fig. 4: ATPase structure and DNA engagement in ATPĪ³S-OCCM, OCCMMcm2RA and OC1MMcm5RA complexes.
From: Unidirectional MCM translocation away from ORC drives origin licensing
a In ATPĪ³S-OCCM (surface representation), Mcm7-4-6-2 ATPases form a right-handed spiral that follows the helicity of DNA. Mcm7, 4 and 6 engage the leading-strand template via a conserved lysine residue of the PS1 hairpin. Mcm2 is not properly engaged with DNA (transparent surface). b In OCCMMcm2RA (cryo-EM density), Mcm7 (transparent density) disengages from DNA and the right-handed ATPase spiral, which is only formed by Mcm4-6-2. Mcm2 binds DNA. DNA contacts involve PS1 hairpins selectively engaging the leading-strand template and h2i hairpins primarily engaging the lagging-strand template. c In OC1MMcm5RA (cryo-EM density), the ATPase domains of Mcm4-6-2-5 form a four-subunit right-handed spiral. Mcm5 engages DNA with the PS1 hairpin binding the leading-strand template and the h2i hairpin binding primarily the lagging-strand template. RA Arginine Finger mutation.
