Master of Science Mateusz P. Sowiński will Friday March 28th, 2025, at 12:15 hold his Thesis Defense for the PhD degree in Science. The title of the thesis is:
«Stable spirocyclic nitroxide spin labels»
Nitroxides are a class of organic radicals that exhibit remarkable stability under ambient conditions due to kinetic, thermodynamic, and electronic factors. Their unpaired electron and stability render nitroxides valuable as probes and polarisation transfer agents in spectroscopy and imaging techniques. In particular, electron paramagnetic resonance (EPR) spectroscopy extensively utilizes nitroxides as spin labels for structural biology applications. These applications require high stability in reducing biological environments and favourable relaxation properties. Both reduction stability and relaxation parameters are heavily influenced by the nitroxide structure, specifically the nature of the substituents at the quaternary α-positions and the nitroxide ring itself. Whilst spirocyclic groups on the nitroxide scaffold provide the latter, such systems are not inherently resistant to reducing conditions. The research presented in this thesis aimed to enhance the stability of spirocyclic nitroxides through various structural modifications and apply these stable probes to investigate protein structures using EPR methods. We conducted comprehensive synthetic, conformational, and kinetic analyses of a diverse panel of spirocyclic nitroxide scaffolds, accompanied by an investigation of their relaxation parameters. We developed three practically applicable spin labels and successfully applied them in protein spin labelling. Recent experiments have demonstrated that these novel spirocyclic spin labels are promising candidates for future use in in-cell EPR measurements.
1st Opponent: Professor Snorri Þór Sigurðsson, School of Engineering and Natural Sciences, University of Iceland
2nd Opponent: Associate Professor Jens Nolsøe, Fakultet for biovitenskap og akvakultur, Nord universitet
Internal member and leader of the committee: Professor Jørn H. Hansen, IK, NT-fak
The defence and trial lecture will be streamed from these following links at Panopto:
Defence (12:15 - 16:00)
Trial Lecture (10:15 - 11:15)
The thesis is available at Munin Here.