6raz | pdb_00006raz

D. melanogaster CMG-DNA, State 2B

Loading... Status: waiting for Mol* initialization Structural highlights 6raz is a 10 chain structure with sequence from Drosophila melanogaster. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy, Resolution 4.46Å Ligands: ADP, ATP Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function O96989_DROME Publication Abstract from PubMed In the eukaryotic replisome, DNA unwinding by the Cdc45-MCM-Go-Ichi-Ni-San (GINS) (CMG) helicase requires a hexameric ring-shaped ATPase named minichromosome maintenance (MCM), which spools single-stranded DNA through its central channel. Not all six ATPase sites are required for unwinding; however, the helicase mechanism is unknown. We imaged ATP-hydrolysis-driven translocation of the CMG using cryo-electron microscopy (cryo-EM) and found that the six MCM subunits engage DNA using four neighboring protomers at a time, with ATP binding promoting DNA engagement. Morphing between different helicase states leads us to suggest a non-symmetric hand-over-hand rotary mechanism, explaining the asymmetric requirements of ATPase function around the MCM ring of the CMG. By imaging of a higher-order replisome assembly, we find that the Mrc1-Csm3-Tof1 fork-stabilization complex strengthens the interaction between parental duplex DNA and the CMG at the fork, which might support the coupling between DNA translocation and fork unwinding. Molecular Basis for ATP-Hydrolysis-Driven DNA Translocation by the CMG Helicase of the Eukaryotic Replisome.,Eickhoff P, Kose HB, Martino F, Petojevic T, Abid Ali F, Locke J, Tamberg N, Nans A, Berger JM, Botchan MR, Yardimci H, Costa A Cell Rep. 2019 Sep 3;28(10):2673-2688.e8. doi: 10.1016/j.celrep.2019.07.104. PMID:31484077 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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