A serotonin-dependent deoxyribozyme that uses light to repair thymine dimers in DNA

Thymine dimers are the most common lesion formed in DNA as a result of exposure to ultraviolet (UV) light. Naturally occurring protein enzymes are known which repair these lesions in different ways. It was hypothesized that in early Earth it may have been RNA that played the functional role, which proteins play today. Also in early Earth it was suspected that the intensity of UV radiation was strong, which could produce dinier products within RNA. A previous in vitro selection has been performed to determine whether DNA was capable of catalyzing a photochemical reaction to reverse this damage. This selection yielded two different deoxyribozymes able to catalyze thymine dimer repair in DNA. The deoxyribozyme SerolC, the topic of this thesis, uses light and serotonin as a cofactor to repair the thymine dimers. Characterization of SerolC provided hypotheses for structure, the proposed reaction mechanism, and aspects of substrate specificity.