Impact of 5-formylcytosine on the melting kinetics of DNA by 1H NMR chemical exchange
2020-07-11
Romeo C A Dubini, Alexander Schön, Markus Müller, Thomas Carell, Petra Rovó
5-Formylcytosine (5fC) is a chemically edited, naturally occurring nucleobase which appears in the context of modified DNA strands. The understanding of the impact of 5fC on dsDNA physical properties is to date limited. In this work, we applied temperature-dependent 1H Chemical Exchange Saturation Transfer (CEST) NMR experiments to non-invasively and site-specifically measure the thermodynamic and kinetic influence of formylated cytosine nucleobase on the melting process involving dsDNA. Incorporation of 5fC within symmetrically positioned CpG sites destabilizes the whole dsDNA structure—as witnessed from the ∼2°C decrease in the melting temperature and 5–10 kJ mol−1 decrease in ΔG°—and affects the kinetic rates of association and dissociation. We observed an up to ∼5-fold enhancement of the dsDNA dissociation and an up to ∼3-fold reduction in ssDNA association rate constants, over multiple temperatures and for several proton reporters. Eyring and van’t Hoff analysis proved that the destabilization is not localized, instead all base-pairs are affected and the transition states resembles the single-stranded conformation. These results advance our knowledge about the role of 5fC as a semi-permanent epigenetic modification and assist in the understanding of its interactions with reader proteins.
Speaker: Prof. Dr. Thomas Carell
Ludwig-Maximilians-Universität München
Institut für Chemische Epigenetik (ICEM)
Department of Chemistry
Office:
Würmtalstrasse 201
81377 Munich
Germany
Mailing address:
Butenandtstr. 5 - 13
81377 Munich
Germany
Phone: +49 (0)89 2180-77750
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Secretary: Birgit Carell
Institute for Chemical Epigenetics Munich (ICEM)
Office:
Würmtalstrasse 201, Haus L - EG / Room: 007
81377 Munich
Germany
Mailing address:
Butenandtstr. 5 - 13
81377 Munich
Germany
Phone: +49 (0)89 2180-77751
Fax: +49 (0)89 2180-77881
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Prof. Dr. Lena Daumann
LMU Munich
Department of Chemistry
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81377 Munich, Germany
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Dr. Sabine Schneider
LMU Munich
Institute for Chemical Epigenetics
Butenandtstr. 5 - 13
House L
81377 Munich, Germany
Phone: +49 89 2180 77716
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Dr. Martin Sumser (Coordinator)
LMU Munich
Institute for Chemical Epigenetics
Butenandtstr. 5 - 13
House L
81377 Munich, Germany
Phone: +49 89 2180 77765
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