Cryo-electron microscopy reveals a novel DNA-binding site on the MCM helicase

Alessandro Costa, Gijs Van Duinen, Barbara Medagli, James Chong, Nozomi Sakakibara, Zvi Kelman, Satish K. Nair, Ardan Patwardhan, Silvia Onesti

Research output: Contribution to journalArticlepeer-review


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.

Original languageEnglish (US)
Pages (from-to)2250-2258
Number of pages9
JournalEMBO Journal
Issue number16
StatePublished - Aug 20 2008


  • AAA+ ATPase
  • Archaea
  • DNA topology
  • Electron microscopy
  • MCM2-7

ASJC Scopus subject areas

  • General Neuroscience
  • Molecular Biology
  • General Biochemistry, Genetics and Molecular Biology
  • General Immunology and Microbiology


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