Oxidation state of the XRCC1 N-terminal domain regulates DNA polymerase β binding affinity

Abstract

Formation of a complex between the XRCC1 N-terminal domain (NTD) and DNA polymerase β (Pol β) is central to base excision repair of damaged DNA. Two crystal forms of XRCC1-NTD complexed with Pol β have been solved, revealing that the XRCC1-NTD is able to adopt a redox-dependent alternate fold, characterized by a disulfide bond, and substantial variations of secondary structure, folding topology, and electrostatic surface. Although most of these structural changes occur distal to the interface, the oxidized XRCC1-NTD forms additional interactions with Pol β, enhancing affinity by an order of magnitude. Transient disulfide bond formation is increasingly recognized as an important molecular regulatory mechanism. The results presented here suggest a paradigm in DNA repair in which the redox state of a scaffolding protein plays an active role in organizing the repair complex.disulfide switch | DNA repair | scaffolding protein

The Ciliopathy-Associated Cep104 Protein Interacts with Tubulin and Nek1 Kinase

“…A PSI-BLAST search with the Cep104 N-terminal region, previously implicated in Cep97 binding (Jiang et al., 2012), retrieved hits to a number of structurally characterized domains of intraflagellar transport protein 25 (IFT25) (Bhogaraju et al., 2011), DNA repair protein XRCC1 (Cuneo and London, 2010), and anaphase-promoting complex APC subunit 10 (Au et al., 2002). These protein domains fold into a nine-stranded β sandwich with a jelly-roll topology and belong to a large superfamily, the founding member of which was a galactose-binding domain of fungal galactose oxidase.…”

The Interaction between Polynucleotide Kinase Phosphatase and the DNA Repair Protein XRCC1 Is Critical for Repair of DNA Alkylation Damage and Stable Association at DNA Damage Sites

“…Although there is atomic resolution structural information for several different regions of XRCC1 (39 -41), only the amino acid change that disrupts the interaction with DNA ligase III␣ occurs within one of these locations, the BRCT II domain (40). The amino acid change that disrupts the interaction with Pol␤ occurs in an unstructured region that is immediately adjacent to that which has been shown to make direct contact with Pol␤, suggesting that the interface between Pol␤ and XRCC1 extends beyond that determined by x-ray crystallography and NMR (41,42).…”

Base Excision Repair Defects Invoke Hypersensitivity to PARP Inhibition

“…V88R XRCC1-transfected cells (XV2 cells) are known to have interrupted binding to pol β (14, 18, 19). Reduced C12A XRCC1 protein transfectants (XRE8 cells), unable to form the C12-C20 disulfide bond and also deficient in interaction with pol β (20), have been characterized previously (14). Another XRCC1 mutant, L360R, was introduced by site-directed mutagenesis of the pDONR221 vector and subcloned into pEF-DEST51.…”