6WGI image
Entry Detail
PDB ID:
6WGI
EMDB ID:
Keywords:
Title:
Atomic model of the mutant OCCM (ORC-Cdc6-Cdt1-Mcm2-7 with Mcm6 WHD truncation) loaded on DNA at 10.5 A resolution
Biological Source:
Source Organism:
PDB Version:
Deposition Date:
2020-04-05
Release Date:
2020-07-15
Method Details:
Experimental Method:
Resolution:
10.00 Å
Aggregation State:
PARTICLE
Reconstruction Method:
SINGLE PARTICLE
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:DNA replication licensing factor MCM2
Chain IDs:J (auth: 2)
Chain Length:868
Number of Molecules:1
Biological Source:Saccharomyces cerevisiae
Polymer Type:polypeptide(L)
Description:DNA replication licensing factor MCM3
Chain IDs:K (auth: 3)
Chain Length:971
Number of Molecules:1
Biological Source:Saccharomyces cerevisiae
Polymer Type:polypeptide(L)
Description:DNA replication licensing factor MCM4
Chain IDs:L (auth: 4)
Chain Length:933
Number of Molecules:1
Biological Source:Saccharomyces cerevisiae
Polymer Type:polypeptide(L)
Description:Minichromosome maintenance protein 5
Chain IDs:M (auth: 5)
Chain Length:775
Number of Molecules:1
Biological Source:Saccharomyces cerevisiae
Polymer Type:polypeptide(L)
Description:DNA replication licensing factor MCM6
Chain IDs:O (auth: 6)
Chain Length:1017
Number of Molecules:1
Biological Source:Saccharomyces cerevisiae
Polymer Type:polypeptide(L)
Description:DNA replication licensing factor MCM7
Chain IDs:P (auth: 7)
Chain Length:845
Number of Molecules:1
Biological Source:Saccharomyces cerevisiae
Polymer Type:polypeptide(L)
Description:Cell division control protein 6
Chain IDs:C (auth: 9)
Chain Length:513
Number of Molecules:1
Biological Source:Saccharomyces cerevisiae
Polymer Type:polypeptide(L)
Description:Origin recognition complex subunit 1
Chain IDs:D (auth: A)
Chain Length:913
Number of Molecules:1
Biological Source:Saccharomyces cerevisiae
Polymer Type:polypeptide(L)
Description:Origin recognition complex subunit 2
Chain IDs:E (auth: B)
Chain Length:620
Number of Molecules:1
Biological Source:Saccharomyces cerevisiae
Polymer Type:polypeptide(L)
Description:Origin recognition complex subunit 3
Chain IDs:F (auth: C)
Chain Length:616
Number of Molecules:1
Biological Source:Saccharomyces cerevisiae
Polymer Type:polypeptide(L)
Description:Origin recognition complex subunit 4
Chain IDs:H (auth: D)
Chain Length:529
Number of Molecules:1
Biological Source:Saccharomyces cerevisiae
Polymer Type:polypeptide(L)
Description:Origin recognition complex subunit 5
Chain IDs:G (auth: E)
Chain Length:479
Number of Molecules:1
Biological Source:Saccharomyces cerevisiae
Polymer Type:polypeptide(L)
Description:Origin recognition complex subunit 6
Chain IDs:I (auth: F)
Chain Length:435
Number of Molecules:1
Biological Source:Saccharomyces cerevisiae
Polymer Type:polydeoxyribonucleotide
Description:DNA (34-MER)
Chain IDs:A (auth: G)
Chain Length:34
Number of Molecules:1
Biological Source:Saccharomyces cerevisiae
Polymer Type:polydeoxyribonucleotide
Description:DNA (34-MER)
Chain IDs:B (auth: H)
Chain Length:34
Number of Molecules:1
Biological Source:Saccharomyces cerevisiae
Polymer Type:polypeptide(L)
Description:Cell division cycle protein CDT1
Chain IDs:N (auth: L)
Chain Length:604
Number of Molecules:1
Biological Source:Saccharomyces cerevisiae
Primary Citation
Structural mechanism of helicase loading onto replication origin DNA by ORC-Cdc6.
Proc.Natl.Acad.Sci.USA 117 17747 17756 (2020)
PMID: 32669428 DOI: 10.1073/pnas.2006231117

Abstact

DNA replication origins serve as sites of replicative helicase loading. In all eukaryotes, the six-subunit origin recognition complex (Orc1-6; ORC) recognizes the replication origin. During late M-phase of the cell-cycle, Cdc6 binds to ORC and the ORC-Cdc6 complex loads in a multistep reaction and, with the help of Cdt1, the core Mcm2-7 helicase onto DNA. A key intermediate is the ORC-Cdc6-Cdt1-Mcm2-7 (OCCM) complex in which DNA has been already inserted into the central channel of Mcm2-7. Until now, it has been unclear how the origin DNA is guided by ORC-Cdc6 and inserted into the Mcm2-7 hexamer. Here, we truncated the C-terminal winged-helix-domain (WHD) of Mcm6 to slow down the loading reaction, thereby capturing two loading intermediates prior to DNA insertion in budding yeast. In "semi-attached OCCM," the Mcm3 and Mcm7 WHDs latch onto ORC-Cdc6 while the main body of the Mcm2-7 hexamer is not connected. In "pre-insertion OCCM," the main body of Mcm2-7 docks onto ORC-Cdc6, and the origin DNA is bent and positioned adjacent to the open DNA entry gate, poised for insertion, at the Mcm2-Mcm5 interface. We used molecular simulations to reveal the dynamic transition from preloading conformers to the loaded conformers in which the loading of Mcm2-7 on DNA is complete and the DNA entry gate is fully closed. Our work provides multiple molecular insights into a key event of eukaryotic DNA replication.

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