Structural and mechanistic insights into Mcm2-7 double-hexamer assembly and function
| Autor: | Jingchuan Sun, Zuanning Yuan, Silvia Tognetti, Christian Speck, Bruce Stillman, Alberto Riera, Alejandra Fernández-Cid, Huilin Li |
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| Rok vydání: | 2014 |
| Předmět: |
PROTEINS
Molecular Conformation ORC/CDC6/MCM2-7 COMPLEX Eukaryotic DNA replication Saccharomyces cerevisiae ORIGIN DNA Biology Random hexamer Pre-replication complex INITIATION Adenosine Triphosphate Control of chromosome duplication Minichromosome maintenance Genetics HELICASE DNA replication initiation 11 Medical and Health Sciences Genetics & Heredity Science & Technology Binding Sites electron microscopy Minichromosome Maintenance Proteins Hydrolysis EUKARYOTIC DNA-REPLICATION Cell Biology 06 Biological Sciences DNA replication origin replicative helicase 17 Psychology and Cognitive Sciences Cell biology Enzyme Activation Microscopy Electron S-PHASE Biochemistry ACTIVE-SITES Origin recognition complex Replisome origin recognition complex prereplication complex ATPASE ACTIVITY Life Sciences & Biomedicine Developmental Biology Protein Binding Research Paper |
| Zdroj: | Genesdevelopment. 28(20) |
| ISSN: | 1549-5477 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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