DNA damage occurs continuously as a result of processes that include bond hydrolysis, deamination, oxidation, alkylation, free radical damage, and damage due to ionizing radiation. Mammalian cells have developed a multicomponent base excision repair (BER) complex in order to combat these DNA damage events. XRCC1 (X-ray cross-complementing group 1) is a multidomain protein that acts as a scaffold to bring together various components of the BER complex. Each domain of XRCC1 interacts with a different BER component. The N-terminal domain, shown here, interacts with DNA polymerase β which is responsible for DNA synthesis at abasic sites.
Marintchev, A., Mullen, M.A., Maciejewski, M.W., Pan, B., Gryk, M.R. and Mullen, G.P. (1999) Solution structure of the single-strand break repair protein XRCC1-N-terminal domain. Nature Structural Biology 6, 884-893.