DNA repair gets physical: Mapping an XPA-binding site on ERCC1

Two recent reports provide new physical information on how the XPA protein recruits the ERCC1–XPF heterodimer to the site of damage during the process of mammalian nucleotide excision repair (NER). Using chemical shift perturbation NMR experiments, the contact sites between a central fragment of ERCC1 and an XPA fragment have been mapped. While both studies agree with regard to the XPA-binding site, they differ on whether the ERCC1–XPA complex can simultaneously bind DNA. These studies have important implications for both the molecular process and the design of potential inhibitors of NER.