Multiple Pathway Relaxation Enhancement in the System Composed of Three Paramagnetic Species: Nitroxide Radical-Ln(3+)-O2.
Longitudinal relaxation of nitroxide spin-labels has been measured for a membrane-incorporated α-helical polypeptide in the presence and absence of residual amounts of membrane-dissolved O2 and paramagnetic Dy(3+) ions. Such a model system, containing three different types of paramagnetic species, provides an important example of nonadditivity of two different relaxation channels for the nitroxide spins.
†Laboratory of Physical Chemistry, ETH, Zurich, Switzerland.
Petra
P
Lueders
‡Laboratory of Biophysics,Wageningen University, Wageningen, The Netherlands.
Heidrun
H
Jäger
‡Laboratory of Biophysics,Wageningen University, Wageningen, The Netherlands.
Marcus A
MA
Hemminga
†Laboratory of Physical Chemistry, ETH, Zurich, Switzerland.
Gunnar
G
Jeschke
†Laboratory of Physical Chemistry, ETH, Zurich, Switzerland.
Maxim
M
Yulikov
EPR; WALP23; distance measurements; lanthanide; lipid bilayer; spin labeling