The elucidation of structure and function of proteins and membrane proteins by EPR spectroscopy has become increasingly important in recent years as technological advances have been made in the design of spectrometers and in the chemistry of the nitroxide group. These new developments have increased the demand for tailor-made amino acids carrying a spin label on the one hand and for reliable me...

We demonstrate the ability of pulsed electron double resonance (PELDOR) experiments to determine the orientation of spin labels in biological macromolecules. Thus, the distance information usually obtained from PELDOR data can be complemented by the mutual orientation of macromolecular domains. A method to determine the angle beta between the spin label normal and the interspin axis is proposed...

We provide a review of current electron spin resonance (ESR) techniques for studying basic molecular mechanisms in membranes and proteins by using nitroxide spin labels. In particular, nitroxide spin label studies with high-field/high-frequency ESR and two-dimensional Fourier transform ESR enable one to accurately determine distances in biomolecules, unravel the details of the complex dynamics ...

The effect of temperature on the permeation of vita­ min C across membranes of DPPC vesicles labelled with the spin label 1,14 has been investigated. It could be shown that at temperatures above 40 °C the permeation rate is diminished considerably despite the fact that, at these temperatures, the spin label can rotate freely (above phase transition temperature) indicating that the membrane is m...

The kinetic behavior of the spin label MAL-6 in the interaction with differently aged human erythrocyte membranes was evaluated by monitoring the rate of disappearance of the room temperature ESR signal due to the MAL-6 spin label added to blood after storage at 4 degrees C or after incubation of red cells at 37 degrees C in a protein-free medium. After 35 days of blood storage or 60 h of eryth...