Imperial College London
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ProfessorChristianSpeck

Faculty of Medicine, Institute of Clinical Sciences

Professor of Genome Biochemistry & Molecular Biology
 
 
 
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Contact

 

+44 (0)7961 815 557chris.speck Website CV

 
 
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Location

 

2.14BLMS BuildingHammersmith Campus

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Summary

 

Publications

Citation

BibTex format

@article{Yuan:2020:10.1073/pnas.2006231117,
author = {Yuan, Z and Schneider, S and Dodd, T and Riera, A and Bai, L and Yan, C and Magdalou, I and Ivanov, I and Stillman, H and Li, H and Speck, C},
doi = {10.1073/pnas.2006231117},
journal = {Proceedings of the National Academy of Sciences of USA},
pages = {17747--17756},
title = {Structural mechanism of helicase loading onto replication origin DNA by ORC-Cdc6},
url = {http://dx.doi.org/10.1073/pnas.2006231117},
volume = {117},
year = {2020}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - 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.
AU  - Yuan,Z
AU  - Schneider,S
AU  - Dodd,T
AU  - Riera,A
AU  - Bai,L
AU  - Yan,C
AU  - Magdalou,I
AU  - Ivanov,I
AU  - Stillman,H
AU  - Li,H
AU  - Speck,C
DO  - 10.1073/pnas.2006231117
EP  - 17756
PY  - 2020///
SN  - 0027-8424
SP  - 17747
TI  - Structural mechanism of helicase loading onto replication origin DNA by ORC-Cdc6
T2  - Proceedings of the National Academy of Sciences of USA
UR  - http://dx.doi.org/10.1073/pnas.2006231117
UR  - http://hdl.handle.net/10044/1/80975
VL  - 117
ER  -
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