First (central) BRCT domain in X-ray repair cross-complementing protein 1 (XRCC1) and similar proteins
XRCC1 is a DNA repair protein that corrects defective DNA strand-break repair and sister chromatid exchange following treatment with ionizing radiation and alkylating agents. It forms homodimers and interacts with polynucleotide kinase (PNK), DNA polymerase-beta (POLB), DNA ligase III (LIG3), APTX, APLF, and APEX1. XRCC1 contains an N-terminal XRCC1-specific domain and two BRCT domains. This family corresponds to the first one.