title: Formation of a ternary complex by human XPA, ERCC1, and ERCC4(XPF) excision repair proteins.
abstract: The xeroderma pigmentosum complementation group A (XP-A) protein, XPA, has recently been expressed in Escherichia coli in a soluble and fully functional form. An affinity column was prepared by linking the XPA protein to a solid support. When HeLa cell-free extract capable of excision repair was applied to the column, > 99.9% of the proteins were in the flow-through. However, the flow-through fraction lacked excision activity. The activity was restored by adding the high salt (1 M KCl) eluate of the column to the flow-through fraction. The XPA protein-bound fraction was tested for specific proteins by an in vitro complementation assay with a panel of cell-free extracts from DNA repair-deficient human and rodent cell lines. The XPA-bound fraction complemented cell-free extracts of excision repair cross-complementing 1 (ERCC-1), ERCC-4 (XP-F), and XP-A mutants. We conclude that the XPA damage recognition protein makes a ternary complex with the ERCC1/ERCC4(XPF) heterodimer with a potential nuclease function.
authors.affiliation: Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill 27599.
authors.forename: C H
authors.initials: CH
authors.lastname: Park
authors.forename: A
authors.initials: A
authors.lastname: Sancar
mesh_terms: D000818:Animals; D002474:Cell-Free System; D002846:Chromatography, Affinity; D003001:Cloning, Molecular; D004249:DNA Damage; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D004720:Endonucleases; D004926:Escherichia coli; D005092:Exonucleases / Q000378:metabolism; D005816:Genetic Complementation Test; D006367:HeLa Cells; D006801:Humans; D011485:Protein Binding; D011506:Proteins / Q000737:chemistry / Q000378:metabolism*; D051760:Xeroderma Pigmentosum Group A Protein
chemical_list: D004268:DNA-Binding Proteins; D011506:Proteins; C497314:XPA protein, human; D051760:Xeroderma Pigmentosum Group A Protein; C095888:xeroderma pigmentosum group F protein; C071447:ERCC1 protein, human; D004720:Endonucleases; D005092:Exonucleases