Structural and mechanistic insights into Mcm2-7 double-hexamer assembly and function

Sun, J., Fernandez-Cid, A., Riera, A., Tognetti, S., Yuan, Z., Stillman, B., Speck, C., Li, H. (2014) Structural and mechanistic insights into Mcm2-7 double-hexamer assembly and function. Genes & Development, 28 (20). pp. 2291-303. ISSN 0890-9369

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URL: http://www.ncbi.nlm.nih.gov/pubmed/25319829
DOI: 10.1101/gad.242313.114

Abstract

Eukaryotic cells license each DNA replication origin during G1 phase by assembling a prereplication complex that contains a Mcm2-7 (minichromosome maintenance proteins 2-7) double hexamer. During S phase, each Mcm2-7 hexamer forms the core of a replicative DNA helicase. However, the mechanisms of origin licensing and helicase activation are poorly understood. The helicase loaders ORC-Cdc6 function to recruit a single Cdt1-Mcm2-7 heptamer to replication origins prior to Cdt1 release and ORC-Cdc6-Mcm2-7 complex formation, but how the second Mcm2-7 hexamer is recruited to promote double-hexamer formation is not well understood. Here, structural evidence for intermediates consisting of an ORC-Cdc6-Mcm2-7 complex and an ORC-Cdc6-Mcm2-7-Mcm2-7 complex are reported, which together provide new insights into DNA licensing. Detailed structural analysis of the loaded Mcm2-7 double-hexamer complex demonstrates that the two hexamers are interlocked and misaligned along the DNA axis and lack ATP hydrolysis activity that is essential for DNA helicase activity. Moreover, we show that the head-to-head juxtaposition of the Mcm2-7 double hexamer generates a new protein interaction surface that creates a multisubunit-binding site for an S-phase protein kinase that is known to activate DNA replication. The data suggest how the double hexamer is assembled and how helicase activity is regulated during DNA licensing, with implications for cell cycle control of DNA replication and genome stability.

Item Type: Paper
Subjects: bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification > DNA replication
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > enzymes > helicase
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > origin recognition complex
CSHL Authors:
Communities: CSHL labs > Stillman lab
CSHL Cancer Center Program > Gene Regulation and Cell Proliferation
Highlight: Stillman, Bruce W.
Depositing User: Matt Covey
Date Deposited: 24 Oct 2014 17:02
Last Modified: 20 Jun 2017 15:59
PMCID: PMC4201289
Related URLs:
URI: http://repository.cshl.edu/id/eprint/30869

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