BPCPPDYSOE21 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 11: Poster A: Single Molecule, Multicellular, Bioimaging, Focus Sessions, etc.
BP 11.13: Poster
Montag, 22. März 2021, 16:30–19:00, BPp
UV-Induced Selectivity of Short DNA Oligonucleotides in Early Evolution — •Corinna L. Kufner1, Dominik B. Bucher2, Wolfgang Zinth3, Christof B. Mast3, Gabriella G. Lozano1, Sukrit Ranjan4, Zoe R. Todd5, and Dimitar D. Sasselov1 — 1Harvard University, USA — 2TU München — 3LMU München — 4Northwestern University, USA — 5University of Washington, USA
At early stages of the evolution of life, between 3.5 and 4.2 billion years ago, the ultraviolet (UV) irradiation on the surface of the Earth was much higher than today. In the prebiotic era, particularly in the absence of complex enzymes, UV light both served as an important energy source for photochemical reactions and imposed a strong selection pressure on the building blocks of life. Here, we study the photophysics of short DNA oligonucleotides by irradiation experiments and ultrafast UV pump (266 nm) IR probe (5-7 um) spectroscopy. We find a strong sequence selectivity in the photostability of short oligonucleotides. Charge transfer states can promote sequence selective self-repair of adjacent photolesions via an entirely intrinsic mechanism which resembles the enzymatic repair by photolyases. Particularly charge transfer states which involve Guanine, the strongest electron donor among the canonical nucleobases, play a key role in the photostability of short oligonucleotides. It may be assumed that photophysical mechanisms have strongly influenced the selection of base sequences at early stages of evolution.