Similar mechanisms for UV damage repair in humans and bacteria Aziz Sancar’s ability to generate knowledge about the molecular details of the process changed the entire research field. He published his findings in 1983. His achievements led to an offer of an associate professorship in biochemistry at the University of North Carolina at Chapel Hill. There, and with the same precision, he mapped the next stages of nucleotide excision repair. In parallel with other researchers, including Tomas Lindahl, Sancar investigated nucleotide excision repair in humans. The molecular machinery that excises UV damage from human DNA is more complex than its bacterial counterpart but, in chemical terms, nucleotide excision repair functions similarly in all organisms. So, what happened to Sancar’s initial interest in photolyase? Well, he eventually returned to this enzyme, uncovering the mechanism responsible for reviving the bacteria. In addition, he helped to demonstrate that a human equivalent to photolyase helps us set the circadian clock. Time to turn to the work of Paul Modrich. He also began with a vague idea about a repair mechanism, which he then chiselled out in elegant molecular detail.