Solution structure of a ERCC1-XPA heterodimer
[ERCC1_HUMAN] Defects in ERCC1 are the cause of cerebro-oculo-facio-skeletal syndrome type 4 (COFS4) [MIM:610758]. COFS is a degenerative autosomal recessive disorder of prenatal onset affecting the brain, eye and spinal cord. After birth, it leads to brain atrophy, hypoplasia of the corpus callosum, hypotonia, cataracts, microcornea, optic atrophy, progressive joint contractures and growth failure. Facial dysmorphism is a constant feature. Abnormalities of the skull, eyes, limbs, heart and kidney also occur. [XPA_HUMAN] Defects in XPA are a cause of xeroderma pigmentosum complementation group A (XP-A) [MIM:278700]; also known as xeroderma pigmentosum type 1 (XP1). XP-A is a rare human autosomal recessive disease characterized by solar sensitivity, high predisposition for developing cancers on areas exposed to sunlight and, in some cases, neurological abnormalities. Group A patients show the most severe skin symptoms and progressive neurological disorders.  
[ERCC1_HUMAN] Structure-specific DNA repair endonuclease responsible for the 5'-incision during DNA repair. [XPA_HUMAN] Involved in DNA excision repair. Initiates repair by binding to damaged sites with various affinities, depending on the photoproduct and the transcriptional state of the region. Required for UV-induced CHEK1 phosphorylation and the recruitment of CEP164 to cyclobutane pyrimidine dimmers (CPD), sites of DNA damage after UV irradiation.
Publication Abstract from PubMed
The nucleotide excision repair (NER) pathway corrects DNA damage caused by sunlight, environmental mutagens and certain antitumor agents. This multistep DNA repair reaction operates by the sequential assembly of protein factors at sites of DNA damage. The efficient recognition of DNA damage and its repair are orchestrated by specific protein-protein and protein-DNA interactions within NER complexes. We have investigated an essential protein-protein interaction of the NER pathway, the binding of the XPA protein to the ERCC1 subunit of the repair endonuclease ERCC1-XPF. The structure of ERCC1 in complex with an XPA peptide shows that only a small region of XPA interacts with ERCC1 to form a stable complex exhibiting submicromolar binding affinity. However, this XPA peptide is a potent inhibitor of NER activity in a cell-free assay, blocking the excision of a cisplatin adduct from DNA. The structure of the peptide inhibitor bound to its target site reveals a binding interface that is amenable to the development of small molecule peptidomimetics that could be used to modulate NER repair activities in vivo.
Structural basis for the recruitment of ERCC1-XPF to nucleotide excision repair complexes by XPA.,Tsodikov OV, Ivanov D, Orelli B, Staresincic L, Shoshani I, Oberman R, Scharer OD, Wagner G, Ellenberger T EMBO J. 2007 Nov 14;26(22):4768-76. Epub 2007 Oct 18. PMID:17948053
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.