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Complex formation by the human Rad51B and Rad51C DNA repair proteins and their activities in vitroThe human Rad51 protein is essential for DNA repair by homologous recombination. In addition to Rad51 protein, five paralogs have been identified: Rad51B/Rad51L1, Rad51C/Rad51L2, Rad51D/Rad51L3, XRCC2, and XRCC3. To further characterize a subset of these proteins, recombinant Rad51, Rad51B-(His)(6), and Rad51C proteins were individually expressed employing the baculovirus system, and each was purified from Sf9 insect cells. Evidence from nickel-nitrilotriacetic acid pull-down experiments demonstrates a highly stable Rad51B.Rad51C heterodimer, which interacts weakly with Rad51. Rad51B and Rad51C proteins were found to bind single- and double-stranded DNA and to preferentially bind 3'-end-tailed double-stranded DNA. The ability to bind DNA was elevated with mixed Rad51 and Rad51C, as well as with mixed Rad51B and Rad51C, compared with that of the individual protein. In addition, both Rad51B and Rad51C exhibit DNA-stimulated ATPase activity. Rad51C displays an ATP-independent apparent DNA strand exchange activity, whereas Rad51B shows no such activity; this apparent strand exchange ability results actually from a duplex DNA destabilization capability of Rad51C. By analogy to the yeast Rad55 and Rad57, our results suggest that Rad51B and Rad51C function through interactions with the human Rad51 recombinase and play a crucial role in the homologous recombinational repair pathway.
Document ID
20040088000
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Lio, Yi-Ching
(Lawrence Berkeley National Laboratory Berkeley, California 94720, United States)
Mazin, Alexander V.
Kowalczykowski, Stephen C.
Chen, David J.
Date Acquired
August 21, 2013
Publication Date
January 24, 2003
Publication Information
Publication: The Journal of biological chemistry
Volume: 278
Issue: 4
ISSN: 0021-9258
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: CA-092584
CONTRACT_GRANT: CA 74046
CONTRACT_GRANT: GM-62653
Distribution Limits
Public
Copyright
Other
Keywords
Non-NASA Center
NASA Discipline Radiation Health

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