The structure of ORC–Cdc6 on an origin DNA reveals the mechanism of ORC activation by the replication initiator Cdc6

Feng, Xiang, Noguchi, Yasunori, Barbon, Marta, Stillman, Bruce, Speck, Christian, Li, Huilin (June 2021) The structure of ORC–Cdc6 on an origin DNA reveals the mechanism of ORC activation by the replication initiator Cdc6. Nature Communications, 12 (1). ISSN 2041-1723

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URL: https://pubmed.ncbi.nlm.nih.gov/34162887/
DOI: 10.1038/s41467-021-24199-1

Abstract

The Origin Recognition Complex (ORC) binds to sites in chromosomes to specify the location of origins of DNA replication. The S. cerevisiae ORC binds to specific DNA sequences throughout the cell cycle but becomes active only when it binds to the replication initiator Cdc6. It has been unclear at the molecular level how Cdc6 activates ORC, converting it to an active recruiter of the Mcm2-7 hexamer, the core of the replicative helicase. Here we report the cryo-EM structure at 3.3 Å resolution of the yeast ORC–Cdc6 bound to an 85-bp ARS1 origin DNA. The structure reveals that Cdc6 contributes to origin DNA recognition via its winged helix domain (WHD) and its initiator-specific motif. Cdc6 binding rearranges a short α-helix in the Orc1 AAA+ domain and the Orc2 WHD, leading to the activation of the Cdc6 ATPase and the formation of the three sites for the recruitment of Mcm2-7, none of which are present in ORC alone. The results illuminate the molecular mechanism of a critical biochemical step in the licensing of eukaryotic replication origins.

Item Type: Paper
Subjects: bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > Cdc6
Investigative techniques and equipment > microscopy > Cryo-electron microscopy
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification > DNA replication
organism description > yeast
CSHL Authors:
Communities: CSHL labs > Stillman lab
SWORD Depositor: CSHL Elements
Highlight: Stillman, Bruce W.
Depositing User: CSHL Elements
Date: 23 June 2021
Date Deposited: 24 Jun 2021 15:29
Last Modified: 12 Jul 2021 17:22
PMCID: PMC8222357
URI: https://repository.cshl.edu/id/eprint/40228

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