Archaeal MCM Proteins as an Analog for the Eukaryotic Mcm2–7 Helicase to Reveal Essential Features of Structure and Function

Figure 6

Features of DNA binding in MCM hexamers. (a) The cocrystal structure of bound to ssDNA revealed that DNA binds in the plane of the hexamer. The DNA binds with a 3′ to 5′ polarity in the clockwise direction around the ring when viewed from the N-terminal side of the hexamer. DNA is shown in yellow and zinc ions are shown as grey spheres. (b) DNA binds across subunit interfaces through interactions between the DNA and MCM Single-Strand Binding (MSSB) residues R186 and R124 (:ssDNA structure, PDB: 4POG), shown in stick. (c) Important residues of the central channel in the MCM hexamer structure (PDB: 4R7Y) with other components transparent. The h2i, ps1β, ACL, MSSB, and N-terminal β-turn motifs are shown in yellow, orange, blue, red, and green, respectively. All structure representations of Figure 6 were prepared with the Pymol software package [88].

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