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Structure of a double hexamer of the Pyrococcus furiosus minichromosome maintenance protein N-terminal domain

Martin Meagher1, Eric J Enemark1

  • 1Department of Structural Biology, St Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA.

Acta Crystallographica. Section F, Structural Biology Communications
|July 6, 2016
PubMed

Insights

The crystal structure of the Pyrococcus furiosus minichromosome maintenance (MCM) protein double hexamer reveals its role in DNA replication. This archaeal MCM complex forms an inactive double hexamer, crucial for initiating DNA unwinding at replication forks.

Area of Science:

  • Biochemistry
  • Structural Biology
  • Molecular Biology

Background:

  • The minichromosome maintenance (MCM) complex is a vital ring-shaped helicase essential for DNA replication in eukaryotes and archaea.
  • MCM complexes assemble as inactive double hexamers at specific DNA sites before replication initiation.

Purpose of the Study:

  • To describe the crystal structure of the N-terminal domain of the Pyrococcus furiosus MCM protein as a double hexamer.
  • To elucidate the structural basis of MCM double-hexamer formation and its role in DNA replication initiation.

Main Methods:

  • X-ray crystallography was used to determine the high-resolution crystal structure of the MCM double hexamer.

Main Results:

  • The structure reveals two MCM hexamers interacting head-to-head, mediated by the N-terminal domain.
  • Minor structural variations were observed compared to previous MCM double-hexamer structures, including a less pronounced head-to-head interaction and reduced inter-hexamer rotation.

Conclusions:

  • The determined structure provides insights into the assembly and regulation of the MCM double hexamer.
  • This structural information is critical for understanding the mechanism of DNA replication initiation in archaea and eukaryotes.
Keywords:
DNA replicationMCMPyrococcus furiosushelicaseminichromosome maintenance

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