[XRCC1_HUMAN] Corrects defective DNA strand-break repair and sister chromatid exchange following treatment with ionizing radiation and alkylating agents. [DPOLB_RAT] Repair polymerase that plays a key role in base-excision repair. Has 5'-deoxyribose-5-phosphate lyase (dRP lyase) activity that removes the 5' sugar phosphate and also acts as a DNA polymerase that adds one nucleotide to the 3' end of the arising single-nucleotide gap. Conducts 'gap-filling' DNA synthesis in a stepwise distributive fashion rather than in a processive fashion as for other DNA polymerases.
Formation of a complex between the XRCC1 N-terminal domain (NTD) and DNA polymerase beta (Pol beta) is central to base excision repair of damaged DNA. Two crystal forms of XRCC1-NTD complexed with Pol beta 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 beta, 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.
Oxidation state of the XRCC1 N-terminal domain regulates DNA polymerase beta binding affinity.,Cuneo MJ, London RE Proc Natl Acad Sci U S A. 2010 Apr 13;107(15):6805-10. Epub 2010 Mar 29. PMID:20351257
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
↑ Cuneo MJ, London RE. Oxidation state of the XRCC1 N-terminal domain regulates DNA polymerase beta binding affinity. Proc Natl Acad Sci U S A. 2010 Apr 13;107(15):6805-10. Epub 2010 Mar 29. PMID:20351257