Lipid-soluble spin labels were incorporated into human lymphocytes and mouse L-cells and the resulting electron spin resonance spectra were compared with spectra obtained from similarly labeled human erythrocytes. Spin labels were found in all subcellular fractions of the nucleated cells that contained membranes. Spinlabeled cells remained viable and capable of replicating in vitro. Electron sp...

Electron paramagnetic resonance (EPR) spectroscopy has increasingly been applied for the study of nucleic acid structure and dynamics. Such studies require incorporation of free radicals (spin labels) into the biopolymer. The labels can be incorporated during chemical synthesis of the oligomer (phosphoramidite approach) or postsynthetically, by reaction of a spin-labeling reagent with a reactiv...

A small, highly aqueous soluble, deuterated, cationic spin label, 4-trimethylammonium-2,2,6,6-tetramethylpiperidine-d17-1-oxyl iodide (dCAT1), was used to directly monitor the negatively charged DMPG vesicle surface in order to test a recent suggestion (Riske et al., Chem. Phys. Lipids, 89 (1997) 31-44) that alterations in the surface potential accompanied apparent phase transitions observed by...