5W7Y

Crystal Structure of FHA domain of human APLF in complex with XRCC1 monophosphorylated mutated peptide

Summary for 5W7Y

• Entry DOI: 10.2210/pdb5w7y/pdb
• Descriptor: Aprataxin and PNK-like factor, DNA repair protein XRCC1 (3 entities in total)
• Functional Keywords: scaffold protein, dna repair, nhej, protein binding
• Biological source: Homo sapiens (Human); More
• Cellular location: Nucleus: Q8IW19 P18887
• Total number of polymer chains: 4
• Total formula weight: 25765.30

Authors

Pedersen, L.C.,Kim, K.,London, R.E. (deposition date: 2017-06-21, release date: 2018-05-02, Last modification date: 2024-10-16)

Primary citation

Kim, K.,Pedersen, L.C.,Kirby, T.W.,DeRose, E.F.,London, R.E.
Characterization of the APLF FHA-XRCC1 phosphopeptide interaction and its structural and functional implications.
Nucleic Acids Res., 45:12374-12387, 2017

PubMed Abstract: Aprataxin and PNKP-like factor (APLF) is a DNA repair factor containing a forkhead-associated (FHA) domain that supports binding to the phosphorylated FHA domain binding motifs (FBMs) in XRCC1 and XRCC4. We have characterized the interaction of the APLF FHA domain with phosphorylated XRCC1 peptides using crystallographic, NMR, and fluorescence polarization studies. The FHA-FBM interactions exhibit significant pH dependence in the physiological range as a consequence of the atypically high pK values of the phosphoserine and phosphothreonine residues and the preference for a dianionic charge state of FHA-bound pThr. These high pK values are characteristic of the polyanionic peptides typically produced by CK2 phosphorylation. Binding affinity is greatly enhanced by residues flanking the crystallographically-defined recognition motif, apparently as a consequence of non-specific electrostatic interactions, supporting the role of XRCC1 in nuclear cotransport of APLF. The FHA domain-dependent interaction of XRCC1 with APLF joins repair scaffolds that support single-strand break repair and non-homologous end joining (NHEJ). It is suggested that for double-strand DNA breaks that have initially formed a complex with PARP1 and its binding partner XRCC1, this interaction acts as a backup attempt to intercept the more error-prone alternative NHEJ repair pathway by recruiting Ku and associated NHEJ factors.

PubMed: 29059378
DOI: 10.1093/nar/gkx941

Experimental method

X-RAY DIFFRACTION (2.1 Å)