For many membrane proteins, the determination of their topology remains a challenge for methods like X-ray crystallography and nuclear magnetic resonance (NMR) spectroscopy. Electron paramagnetic resonance (EPR) spectroscopy has evolved as an alternative technique to study structure and dynamics of membrane proteins. The present study demonstrates the feasibility of membrane protein topology de...

The ability to track drug binding and release makes electron paramagnetic resonance (EPR) spectroscopy well suited for drug delivery studies. Using the continuous wave (cw) EPR technique to extract information about the dynamics of the spin labeled drugs we can simultaneously determine the bound and unbound drugs. Here, spin labeled salicylic acid (SLSA) binding to and release from bovine serum...

Through the use of site-directed mutagenesis and chemical rescue, we have identified the proton acceptor for redox-active tyrosine D in photosystem II (PSII). Effects of chemical rescue on the tyrosyl radical were monitored by EPR spectroscopy. We also have acquired the Fourier-transform infrared (FT-IR) spectrum associated with the oxidation of tyrosine D and concomitant protonation of the acc...

The spin-labeled nucleoside (T)C, containing 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) conjugated to the exocyclic amino group of C, was used to detect single-base mismatches in duplex DNA for the first time by electron paramagnetic resonance (EPR) spectroscopy. Furthermore, the EPR spectra of the fully base-paired duplex ((T)C.G) and the mismatches ((T)C.A, (T)C.C, and (T)C.T) were signific...

Heat treatment of the bovine cytochrome c oxidase complex in the zwitterionic detergent sulfobetaine 12 (SB-12) results in loss of subunit III and the appearance of a type II copper center as characterized by electron paramagnetic resonance (EPR) spectroscopy. Previous authors (Nilsson, T., Copeland, R. A., Smith, P. A., and Chan, S. I. (1988) Biochemistry 27, 8254-8260) have interpreted this t...

Complex of bismuth, an anti-inflammatory drug, was studied by EPR spectroscopy. The aim of this study was to determine concentrations and properties of free radicals formed during thermal sterilization of bismuth subgallate according to pharmacopoeia norms to optimize its sterilization process. Different temperatures (160°C, 170°C, and 180°C) and times (120 minutes, 60 minutes, and 30 minutes) ...

Reported here are the syntheses and characterization of cobaloximes that feature a bis(imino)acenaphthene (BIAN) appended ligand. The X-ray crystal structures and spectroscopy ((1)H NMR or EPR) of the complexes within the series [Co(aqdBF2)2(MeCN)2] (), [Co(aqdBF2)(MeCN)2](-) () and [Co(aqdBF2)2(MeCN)2](2-) (, ) are reported and the 3-electron reduced complex [Co(aqdBF2)2(MeCN)2](3-) () has bee...

Noncovalent site-directed spin labeling (NC-SDSL) of abasic sites in duplex DNAs with the spin label ç, a cytosine analogue, is a promising approach for spin-labeling nucleic acids for EPR spectroscopy. In an attempt to increase the affinity of ç for abasic sites, several N3 derivatives were prepared, and their binding affinities were determined by EPR spectroscopy. Most of the N3 substituents ...

OBJECTIVE The involvement of transition metals in atherosclerosis is controversial. Some epidemiological studies have reported a relationship between iron (Fe) and cardiovascular disease, whereas others have not. Experimental studies have reported elevated levels of iron and copper (Cu) in diseased human arteries but have often used methods that release metal ions from proteins. METHODS AND R...

Within this review, we describe a home-built pulsed electron paramagnetic resonance (EPR) spectrometer operating at 180 GHz as well as the incorporation of two double resonance techniques, electron nuclear double resonance (ENDOR) and pulsed electron double resonance (PELDOR), along with first applications. Hahn-echo decays on a TEMPO/polystyrene sample are presented, demonstrating that the obs...