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Understanding the structure and role of DNA-PK in NHEJ: How X-ray diffraction and cryo-EM contribute in complementary ways.

Accepted version
Peer-reviewed

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Type

Article

Change log

Authors

Wu, Qian 
Ochi, Takashi 
Chirgadze, Dimitri Y 
Huiskonen, Juha T 

Abstract

DNA double-strand breaks (DSBs), generated by ionizing radiation, reactive oxygen species and DNA replication across nicks, are the most severe DNA damage in eukaryotic cells. Non-Homologous End Joining repairs DNA double-strand breaks directly without a template and so can take place at any point in the cell cycle. Ku70/80 heterodimers rapidly assemble around broken DNA ends, allowing DNA-PKcs, the catalytic subunit of DNA-dependent protein kinase, to be recruited and facilitating synapsis of broken DNA ends. This then provides a stage for end-processing and ligation. Here we review progress leading in 2017 to the medium resolution X-ray structure of DNA-PKcs, a single polypeptide chain of 4128 amino acids. This was followed quickly by chain tracing of cryo-EM structures of DNA-PKcs in complex with Ku and DNA. We discuss how combination of structural information from X-ray and cryo-EM studies can produce a working model for complex multicomponent molecular assemblies such as those found in DNA-double-strand-break repair.

Description

Keywords

Cryo-EM, DNA repair, DNA-PK, DNA-PKcs, DSBs, Ku70/80, NHEJ, X-ray crystallography, Animals, Cryoelectron Microscopy, Crystallography, X-Ray, DNA End-Joining Repair, DNA-Activated Protein Kinase, Humans, Protein Domains

Journal Title

Prog Biophys Mol Biol

Conference Name

Journal ISSN

0079-6107
1873-1732

Volume Title

147

Publisher

Elsevier BV
Sponsorship
Wellcome Trust (200814/Z/16/Z)