Ku78

Ku70 and Ku80 are 70kDa and 80kDa subunits of the Lupus Ku autoantigen
Ku78
SMART accession number:SM00559
Description: This is a single stranded DNA- and ATP-depedent helicase that has a role in chromosome translocation. This is a domain of unknown function C-terminal to its von Willebrand factor A domain, that also occurs in bacterial hypothetical proteins.
Interpro abstract (IPR006164):

The Ku heterodimer is composed of Ku70 and Ku80 (or Ku86), 70 kDa and 80 kDa subunits of an ATP-dependent DNA helicase, which contributes to genomic integrity through its ability to bind DNA double-stranded breaks and facilitate repair by the non-homologous end-joining pathway. This is the central DNA-binding beta-barrel domain and is found in both the Ku70 and Ku80 proteins. Ku makes only a few contacts with the sugar-phosphate backbone, and none with the DNA bases, but it fits sterically to major and minor groove contours forming a ring that encircles duplex DNA, cradling two full turns of the DNA molecule. By forming a bridge between the broken DNA ends, Ku acts to structurally support and align the DNA ends, to protect them from degradation, and to prevent promiscuous binding to unbroken DNA. Ku effectively aligns the DNA, while still allowing access of polymerases, nucleases and ligases to the broken DNA ends to promote end joining [(PUBMED:11483577)].

GO process:double-strand break repair via nonhomologous end joining (GO:0006303)
GO function:ATP-dependent DNA helicase activity (GO:0004003), DNA binding (GO:0003677)
Family alignment:
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There are 422 Ku78 domains in 422 proteins in SMART's nrdb database.

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