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Cryo‐electron microscopy reveals a novel DNA‐binding site on the MCM helicase
Author(s) -
Costa Alessandro,
van Duinen Gijs,
Medagli Barbara,
Chong James,
Sakakibara Nozomi,
Kelman Zvi,
Nair Satish K,
Patwardhan Ardan,
Onesti Silvia
Publication year - 2008
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1038/emboj.2008.135
Subject(s) - biology , helicase , dna , cryo electron microscopy , electron microscope , binding site , biophysics , microbiology and biotechnology , microscopy , evolutionary biology , genetics , computational biology , gene , rna , optics , physics
The eukaryotic MCM2–7 complex is recruited at origins of replication during the G1 phase and acts as the main helicase at the replication fork during the S phase of the cell cycle. To characterize the interplay between the MCM helicase and DNA prior to the melting of the double helix, we determined the structure of an archaeal MCM orthologue bound to a 5.6‐kb double‐stranded DNA segment, using cryo‐electron microscopy. DNA wraps around the N‐terminal face of a single hexameric ring. This interaction requires a conformational change within the outer belt of the MCM N‐terminal domain, exposing a previously unrecognized helix‐turn‐helix DNA‐binding motif. Our findings provide novel insights into the role of the MCM complex during the initiation step of DNA replication.