Aziz Sancar

Aziz Sancar, a Turkish-American molecular biologist, won the 2015 Nobel Prize in Chemistry with Tomas Lindahl and Paul L. Modrich for detailing how cells repair damaged DNA. His research focuses on DNA repair, cell cycle checkpoints, and the circadian clock. He holds the Sarah Graham Kenan Professorship of Biochemistry and Biophysics at the University of North Carolina School of Medicine and is affiliated with the UNC Lineberger Comprehensive Cancer Center. Together with his wife, Gwen Boles Sancar, he founded the Aziz & Gwen Sancar Foundation, a nonprofit that promotes Turkish culture and supports Turkish students in the United States.

Born on 8 September 1946 in the Savur district of Mardin Province, southeastern Turkey, Sancar grew up in a lower-middle-class family as the seventh of eight children. His parents were uneducated but prioritized his schooling. He was inspired by teachers trained in the Village Institutes. Though he wanted to study chemistry, he followed five classmates into medicine, earning his MD from Istanbul University in 1969 as the top student. He then worked as a doctor in Savur for 1.5 years. A TÜBİTAK scholarship took him to Johns Hopkins University for biochemistry, but after 1.5 years he returned to Savur, struggling to adapt and speaking only French. He later wrote to Claud Stan Rupert, a DNA repair researcher who had moved to the University of Texas at Dallas, and completed a PhD there in 1977 on the photoreactivating enzyme of *E. coli*. In 1976, as part of his dissertation, he replicated the gene for photolyase, an enzyme that repairs UV-induced thymine dimers.

After three rejected postdoctoral applications, Sancar worked as a lab technician at Yale University for five years. There, he began his field-changing work on nucleotide excision repair, a DNA repair mechanism that works in darkness. In Dean Rupp’s lab, he identified the UvrABC endonuclease and its genes, discovering that these enzymes cut the damaged DNA strand twice, removing 12–13 nucleotides. He then applied to 50 universities and received only one positive response—a lecturer position at the University of North Carolina. He later noted that his English accent hurt his career. At Chapel Hill, he uncovered further steps of bacterial nucleotide excision repair and studied the more complex human version. His longest-running work involves photolyase and photo-reactivation; in his inaugural PNAS article, he captured the photolyase radicals he had pursued for nearly 20 years, directly observing the photocycle for thymine dimer repair.

Sancar was elected to the National Academy of Sciences in 2005, the first Turkish member. He is an honorary member of the Turkish Academy of Sciences and the American Academy of Arts and Sciences. He married Gwen Boles Sancar, who graduated the same year. Regarding his ethnic background, Sancar has stated he is Turkish, speaking Arabic with his parents and Turkish with his siblings. When asked by the BBC if he was “a Turk or half-Arab,” he replied, “I’m a Turk, that’s it.” His cousin, politician Mithat Sancar, has said the family is Arab. During his Istanbul University years, Sancar was involved with the far-right Turkish ultranationalist Grey Wolves.