Real-time observation of enzymatic processes on DNA
4 May 2020
Scientists at the University of Konstanz have used infrared spectroscopy to visualise the biochemical processes that take place at DNA strand breaks involving PARP1. These observations could provide important insight into the dynamic changes in the protein structure.
Cross-departmental working groups, led by Professor Aswin Mangerich and Professor Alexander Bürkle, Department of Biology, and Professor Karin Hauser, Department of Chemistry have applyied a recently developed ATR-FTIR spectroscopic approach combining surface passivation and specific immobilisation, to direct and holistic insights into the molecular mechanisms underlying PARP1-dependent PARylation in a time-resolved manner.
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.
Even though PARP1 was discovered more than five decades ago12, the dynamics of the PARylation reaction and consequences on PARP1 structure are still incompletely understood. Performing reaction-induced difference spectroscopy enables monitoring of small structural changes of proteins upon molecular interactions or enzymatic reactions in real time. The specific immobilisation of molecules of interest at the ATR-crystal surface enhances the local surface concentration and thus improves the signal-to-noise ratio even at low analyte concentrations, thus providing an excellent platform to study the molecular mechanisms of PARylation.