Dresden 2009 – wissenschaftliches Programm
CPP 16.14: Poster
Dienstag, 24. März 2009, 14:00–16:30, P3
CIDNP as a tool for determining the structure and magnetic resonance parameters of transient radicals of biomolecules — •Talea Köchling1, Gerald Hörner2, Sergey Korchak1, Alexandra Yurkovskaya1,3, and Hans-Martin Vieth1 — 1Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin — 2Chemical Physics Department, Faculty of Chemistry, Adam Mickiewicz University Poznan — 3International Tomography Center, Institutskaya 3a, Novosibirsk, Russia
Combining NMR spectroscopy with the effect of spin hyperpolarization opens new ways to get information about structure of transient radicals and their pathways. A way for creating transient non-thermal signal amplitudes in proteins is Chemically Induced Dynamic Nuclear Polarization (CIDNP) resulting from the formation of a radical pair of a photo-excited dye molecule and an amino acid residue. Field dependence of CIDNP allows to determine structure and magnetic resonance parameters (hyperfine coupling constants and g-factor) of elusive radicals. Furthermore, from time dependence with microsecond resolution it is possible to differentiate geminate and bulk processes, so that reaction pathways and rate constants of dynamic processes can be extracted.
In present study, CIDNP results for free amino acids and different peptides containing combination of methionine, glycine and tyrosine in aqueous solution at ambient temperature are obtained. Dependence of intramolecular electron transfer in the peptides on pH and its pathways are discussed.