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CIDNP study of photochemically generated short lived radical intermediates of biologically important molecules

Final Activity Report Summary - CIDNP_of_BM (CIDNP study of photochemically generated short lived radical intermediates of biologically important molecules)

Experimental and theoretical techniques based on magnetic resonance were developed and applied to obtain data on the structure and reactivity of radical states of structural building blocks of proteins and nucleic acids, namely amino acids and nucleotides, which were crucial for understanding the mechanisms of numerous biochemical processes. The results of these studies were used to probe the structure and dynamics of native and unfolded proteins with promising subsequent applications in numerous branches of biochemistry.

The modelling of non-enzymatic deoxyribonucleic acid (DNA) repair by electron transfer from amino acids to oxidised purine nucleotide guanosine monophosphate was studied as a prototype of fast chemical repair of radiation-induced DNA damages. We showed that chemically-induced dynamic nuclear polarisation (CIDNP), in particular its field dependence and time-resolved version, could be applied as routine techniques for determining the magnetic resonance parameters of elusive radical species that could not be detected by electron paramagnetic resonance (EPR) spectroscopy. In addition, the CIDNP technique was used as tool for protein studies, providing a strong signal enhancement compared to conventional nuclear magnetic resonance (NMR) and giving new information on residue accessibility and mobility in proteins in different states, thus allowing for obtaining quantitative data about correlation times of intramolecular motions of residues on the nanosecond timescale.