image: Infrared spectra at different points of time (0-79 min) after the poly(ADP-ribosyl)ation reaction started due to the addition of PARP1 substrate NAD+. The following can be observed: the dynamic formation of the biopolymer poly(ADP-ribose) (absorption bands at 1236 cm-1 and 1074 cm-1) and the detachment of PARP1 from the DNA strand break (absorption bands at 1645 cm-1 and 1548 cm-1).
DNA strand breaks can lead to cell death or to mutations and thus contribute in the long term to cancer development or the ageing process. Fortunately, cells possess molecular tools to repair such DNA strand breaks very efficiently. One of them is the enzyme poly(ADP-ribose) polymerase 1 (PARP1), which detects DNA strand breaks and thereby initiates downstream repair processes.
Scientists at the University of Konstanz (working groups of Professor Aswin Mangerich and Professor Alexander Bürkle, Department of Biology, and working group of Professor Karin Hauser, Department of Chemistry) have now been able to visualize in detail, by means of infrared spectroscopy, the biochemical processes that take place at DNA strand breaks involving PARP1, and could consequently provide important insight into the dynamic changes in the protein structure.