Radical Reactions in Biological Systems
Electron Transfer through DNA and Peptides
Long range charge transfer through DNA and Peptides is possible via a hopping mechanism that depends upon the sequence. This long range charge transfer allows the determination of the sequences and mismatches of DNA double strands.
Radical-Induced DNA and Peptide Cleavage
We have synthesized modified nucleotides and peptides that function as radical precursors. Irradiation leads to a selective bond cleavage. The mechanism of this strand scission is studied and the applications for enzyme-free cleavages are worked out.
A new signal transduction pathway is studied using the cyclic dimer of guanosyl phosphate. Repair enzymes are tested with modified DNA strands.
Signal Transduction and Enzyme Inhibition
We develop new synthesis for bioactive compounds in the area of signal transduction (c-di-GMP) and kinase inhibition.
Stereoselective Synthesis with Radicals and Biradicals
Photoinduced H-abstraction leads to biradicals. We use this method for the formation of cyclic amino acids in peptides and study the influence of this "reagentless" transformation on the conformation of peptides. During these experiments we have observed enantioselective cyclization reactions that are based on a memory effect of chirality. This is especially the case with singlet biradicals whereas the stereoselectivity of triplet biradicals can be induced by substrate or auxiliary control.
New Photocleavable Protecting Groups
We have developed new photocleavable protecting groups that are compatible with many reagents and reactions. These protecting groups are applied in organic synthesis and combinatorial chemistry.