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|2w3o, resolution 1.85Å ()|
|Related:||1cdz, 1xnt, 2brf, 1xna, 2d8m|
CRYSTAL STRUCTURE OF THE HUMAN PNKP FHA DOMAIN IN COMPLEX WITH AN XRCC1-DERIVED PHOSPHOPEPTIDE
Short-patch repair of DNA single-strand breaks and gaps (SSB) is coordinated by XRCC1, a scaffold protein that recruits the DNA polymerase and DNA ligase required for filling and sealing the damaged strand. XRCC1 can also recruit end-processing enzymes, such as PNK (polynucleotide kinase 3'-phosphatase), Aprataxin and APLF (aprataxin/PNK-like factor), which ensure the availability of a free 3'-hydroxyl on one side of the gap, and a 5'-phosphate group on the other, for the polymerase and ligase reactions respectively. PNK binds to a phosphorylated segment of XRCC1 (between its two C-terminal BRCT domains) via its Forkhead-associated (FHA) domain. We show here, contrary to previous studies, that the FHA domain of PNK binds specifically, and with high affinity to a multiply phosphorylated motif in XRCC1 containing a pSer-pThr dipeptide, and forms a 2:1 PNK:XRCC1 complex. The high-resolution crystal structure of a PNK-FHA-XRCC1 phosphopeptide complex reveals the basis for this unusual bis-phosphopeptide recognition, which is probably a common feature of the known XRCC1-associating end-processing enzymes.
Specific recognition of a multiply phosphorylated motif in the DNA repair scaffold XRCC1 by the FHA domain of human PNK., Ali AA, Jukes RM, Pearl LH, Oliver AW, Nucleic Acids Res. 2009 Jan 20. PMID:19155274
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
[XRCC1_HUMAN] Corrects defective DNA strand-break repair and sister chromatid exchange following treatment with ionizing radiation and alkylating agents.