A recent study shows that conformational proofreading is used by human DNA repair mechanisms. The research focused on the question of how DNA-repair proteins scan the human genome for UV-induced damage during the initial step of nucleotide excision repair (NER). Detailed single-molecule measurements revealed how the human UV-damaged DNA-binding protein (UV-DDB) performs a 3D search. The authors find that  "UV-DDB examines sites on DNA in discrete steps before forming long-lived, nonmotile UV-DDB dimers (DDB1-DDB2) at sites of damage. Analysis of the rates of dissociation for the transient binding molecules on both undamaged and damaged DNA show multiple dwell times over three orders of magnitude... These intermediate states are believed to represent discrete UV-DDB conformers on the trajectory to stable damage detection." The authors conclude from their detailed kinetic measurements that UV-DDB recognizes lesions using a conformational proofreading mechanism via multiple intermediates.