5BK4

Cryo-EM structure of Mcm2-7 double hexamer on dsDNA


Experimental Data Snapshot

  • Method: ELECTRON MICROSCOPY
  • Resolution: 3.9 Å
  • Aggregation State: PARTICLE 
  • Reconstruction Method: SINGLE PARTICLE 

wwPDB Validation 3D Report Full Report


This is version 1.4 of the entry. See complete history

Literature

Cryo-EM structure of Mcm2-7 double hexamer on DNA suggests a lagging-strand DNA extrusion model.

Noguchi, Y.Yuan, Z.Bai, L.Schneider, S.Zhao, G.Stillman, B.Speck, C.Li, H.

(2017) Proc. Natl. Acad. Sci. U.S.A. 114: E9529-E9538

  • DOI: 10.1073/pnas.1712537114

  • PubMed Abstract: 
  • During replication initiation, the core component of the helicase-the Mcm2-7 hexamer-is loaded on origin DNA as a double hexamer (DH). The two ring-shaped hexamers are staggered, leading to a kinked axial channel. How the origin DNA interacts with th ...

    During replication initiation, the core component of the helicase-the Mcm2-7 hexamer-is loaded on origin DNA as a double hexamer (DH). The two ring-shaped hexamers are staggered, leading to a kinked axial channel. How the origin DNA interacts with the axial channel is not understood, but the interaction could provide key insights into Mcm2-7 function and regulation. Here, we report the cryo-EM structure of the Mcm2-7 DH on dsDNA and show that the DNA is zigzagged inside the central channel. Several of the Mcm subunit DNA-binding loops, such as the oligosaccharide-oligonucleotide loops, helix 2 insertion loops, and presensor 1 (PS1) loops, are well defined, and many of them interact extensively with the DNA. The PS1 loops of Mcm 3, 4, 6, and 7, but not 2 and 5, engage the lagging strand with an approximate step size of one base per subunit. Staggered coupling of the two opposing hexamers positions the DNA right in front of the two Mcm2-Mcm5 gates, with each strand being pressed against one gate. The architecture suggests that lagging-strand extrusion initiates in the middle of the DH that is composed of the zinc finger domains of both hexamers. To convert the Mcm2-7 DH structure into the Mcm2-7 hexamer structure found in the active helicase, the N-tier ring of the Mcm2-7 hexamer in the DH-dsDNA needs to tilt and shift laterally. We suggest that these N-tier ring movements cause the DNA strand separation and lagging-strand extrusion.


    Organizational Affiliation

    DNA Replication Group, Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London W12 0NN, United Kingdom.




Macromolecules

Find similar proteins by: Sequence  |  Structure


Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
DNA replication licensing factor MCM2
2, A
868Saccharomyces cerevisiae (strain ATCC 204508 / S288c)Mutation(s): 0 
Gene Names: MCM2
EC: 3.6.4.12
Find proteins for P29469 (Saccharomyces cerevisiae (strain ATCC 204508 / S288c))
Go to Gene View: MCM2
Go to UniProtKB:  P29469
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
DNA replication licensing factor MCM3
3, B
971Saccharomyces cerevisiae (strain ATCC 204508 / S288c)Mutation(s): 0 
Gene Names: MCM3
EC: 3.6.4.12
Find proteins for P24279 (Saccharomyces cerevisiae (strain ATCC 204508 / S288c))
Go to Gene View: MCM3
Go to UniProtKB:  P24279
Entity ID: 3
MoleculeChainsSequence LengthOrganismDetails
DNA replication licensing factor MCM4
4, C
933Saccharomyces cerevisiae (strain ATCC 204508 / S288c)Mutation(s): 0 
Gene Names: MCM4 (CDC54, HCD21)
EC: 3.6.4.12
Find proteins for P30665 (Saccharomyces cerevisiae (strain ATCC 204508 / S288c))
Go to Gene View: MCM4
Go to UniProtKB:  P30665
Entity ID: 4
MoleculeChainsSequence LengthOrganismDetails
DNA replication licensing factor MCM5
5, D
775Saccharomyces cerevisiae (strain ATCC 204508 / S288c)Mutation(s): 0 
Gene Names: MCM5 (CDC46)
EC: 3.6.4.12
Find proteins for P29496 (Saccharomyces cerevisiae (strain ATCC 204508 / S288c))
Go to Gene View: MCM5
Go to UniProtKB:  P29496
Entity ID: 5
MoleculeChainsSequence LengthOrganismDetails
DNA replication licensing factor MCM6
6, E
1017Saccharomyces cerevisiae (strain ATCC 204508 / S288c)Mutation(s): 0 
Gene Names: MCM6
EC: 3.6.4.12
Find proteins for P53091 (Saccharomyces cerevisiae (strain ATCC 204508 / S288c))
Go to Gene View: MCM6
Go to UniProtKB:  P53091
Entity ID: 6
MoleculeChainsSequence LengthOrganismDetails
DNA replication licensing factor MCM7
7, F
845Saccharomyces cerevisiae (strain ATCC 204508 / S288c)Mutation(s): 0 
Gene Names: MCM7 (CDC47)
EC: 3.6.4.12
Find proteins for P38132 (Saccharomyces cerevisiae (strain ATCC 204508 / S288c))
Go to Gene View: MCM7
Go to UniProtKB:  P38132
Entity ID: 7
MoleculeChainsLengthOrganism
DNA (60-mer), strand 1S60Saccharomyces cerevisiae
Entity ID: 8
MoleculeChainsLengthOrganism
DNA (60-mer), strand 2O60Saccharomyces cerevisiae
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
ADP
Query on ADP

Download SDF File 
Download CCD File 
2, 3, 5, 7, A, B, D, F
ADENOSINE-5'-DIPHOSPHATE
C10 H15 N5 O10 P2
XTWYTFMLZFPYCI-KQYNXXCUSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: ELECTRON MICROSCOPY
  • Resolution: 3.9 Å
  • Aggregation State: PARTICLE 
  • Reconstruction Method: SINGLE PARTICLE 
Software Package:
Software NamePurpose
PHENIXrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History & Funding Information

Deposition Data

  • Deposited Date: 2017-09-12 
  • Released Date: 2017-10-25 
  • Deposition Author(s): Li, H., Yuan, Z., Bai, L.

Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute of General Medical SciencesUnited StatesGM111472

Revision History 

  • Version 1.0: 2017-10-25
    Type: Initial release
  • Version 1.1: 2017-11-08
    Type: Database references
  • Version 1.2: 2017-11-22
    Type: Database references
  • Version 1.3: 2017-12-06
    Type: Author supporting evidence
  • Version 1.4: 2018-07-18
    Type: Data collection