Dresden 2003 – wissenschaftliches Programm
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CPP: Chemische Physik und Polymerphysik
CPP 3: Biomoleküle
CPP 3.9: Vortrag
Montag, 24. März 2003, 12:15–12:30, ZEU/118
CIDNP study of structure and dynamics of proteins and protein related compounds — •Alexandra Yurkovskaya1, Olga Morozova1, Konstantin Ivanov1, and Hans-Martin Vieth2 — 1International Tomography Center, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia — 2Department of Physics, Free University of Berlin, D-14195 Berlin, Germany
Chemically Induced Dynamic Nuclear Polarization (CIDNP) is a method that has successfully been applied to study protein structure and dynamics. Here we report on time-resolved CIDNP in combination with the magnetic field dependence of CIDNP applied to reveal the driving forces for formation of spin polarization in a comparative study of photoreactions involving aromatic amino acids, peptides, and proteins in native and denatured states. For the amino acids CIDNP pattern and field dependence are determined by the magnetic resonance parameters of transient radicals (g-factors and hyperfine constants), and by the precursor spin state. The quantitative analysis of CIDNP kinetics in histidine, tyrosine and tryptophan provides information on relaxation of intermediate species and rate constants of degenerate electron exchange between the radicals and diamagnetic molecules of amino acids. In peptides intramolecular electron transfer (IET) is revealed to have a significant effect. The influence of such secondary effects on the analysis of protein properties by CIDNP will be discussed.
Acknowledgement. This work was supported by AvH, DFG (Vi103/9), and INTAS (01-2126)