title: Characterization of the redox transition of the XRCC1 N-terminal domain.
abstract: XRCC1, a scaffold protein involved in DNA repair, contains an N-terminal domain (X1NTD) that interacts specifically with DNA polymerase β. It was recently discovered that X1NTD contains a disulfide switch that allows it to adopt either of two metamorphic structures. In the present study, we demonstrate that formation of an N-terminal proline carbimate adduct resulting from the nonenzymatic reaction of Pro2 with CO2 is essential for stabilizing the oxidized structure, X1NTDox. The kinetic response of X1NTDred to H2O2, monitored by NMR, was determined to be very slow, consistent with involvement of the buried, kinetically trapped Cys12 residue, but was significantly accelerated by addition of protein disulfide isomerase or by Cu(2+). NMR analysis of a sample containing the pol β polymerase domain, and both the reduced and oxidized forms of X1NTD, indicates that the oxidized form binds to the enzyme 25-fold more tightly than the reduced form.
authors.affiliation: Laboratory of Structural Biology, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA.
authors.forename: Scott A
authors.initials: SA
authors.lastname: Gabel
authors.affiliation: Laboratory of Structural Biology, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA.
authors.forename: Cassandra E
authors.initials: CE
authors.lastname: Smith
authors.affiliation: Laboratory of Structural Biology, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Cuneo
authors.affiliation: Laboratory of Structural Biology, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA.
authors.forename: Geoffrey A
authors.initials: GA
authors.lastname: Mueller
authors.affiliation: Laboratory of Structural Biology, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA.
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Kirby
authors.affiliation: Laboratory of Structural Biology, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA.
authors.forename: Eugene F
authors.initials: EF
authors.lastname: DeRose
authors.affiliation: Laboratory of Structural Biology, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA.
authors.forename: Juno M
authors.initials: JM
authors.lastname: Krahn
authors.affiliation: Laboratory of Structural Biology, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA. Electronic address: london@niehs.nih.gov.
authors.forename: Robert E
authors.initials: RE
authors.lastname: London
mesh_terms: D002460:Cell Line; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004926:Escherichia coli; D008958:Models, Molecular; D010084:Oxidation-Reduction; D011485:Protein Binding; D017510:Protein Folding; D000076105:X-ray Repair Cross Complementing Protein 1
chemical_list: D004268:DNA-Binding Proteins; D000076105:X-ray Repair Cross Complementing Protein 1